diff --git a/src/imap/client.rs b/src/imap/client.rs
index e93b273b8..2ee8165d1 100644
--- a/src/imap/client.rs
+++ b/src/imap/client.rs
@@ -7,7 +7,7 @@ use async_imap::{
 use async_std::net::{self, TcpStream};
 
 use super::session::Session;
-use crate::login_param::{dc_build_tls, CertificateChecks};
+use crate::login_param::dc_build_tls;
 
 use super::session::SessionStream;
 
@@ -78,10 +78,10 @@ impl Client {
     pub async fn connect_secure<A: net::ToSocketAddrs, S: AsRef<str>>(
         addr: A,
         domain: S,
-        certificate_checks: CertificateChecks,
+        strict_tls: bool,
     ) -> ImapResult<Self> {
         let stream = TcpStream::connect(addr).await?;
-        let tls = dc_build_tls(certificate_checks);
+        let tls = dc_build_tls(strict_tls);
         let tls_stream: Box<dyn SessionStream> =
             Box::new(tls.connect(domain.as_ref(), stream).await?);
         let mut client = ImapClient::new(tls_stream);
@@ -118,16 +118,12 @@ impl Client {
         })
     }
 
-    pub async fn secure<S: AsRef<str>>(
-        self,
-        domain: S,
-        certificate_checks: CertificateChecks,
-    ) -> ImapResult<Client> {
+    pub async fn secure<S: AsRef<str>>(self, domain: S, strict_tls: bool) -> ImapResult<Client> {
         if self.is_secure {
             Ok(self)
         } else {
             let Client { mut inner, .. } = self;
-            let tls = dc_build_tls(certificate_checks);
+            let tls = dc_build_tls(strict_tls);
             inner.run_command_and_check_ok("STARTTLS", None).await?;
 
             let stream = inner.into_inner();
diff --git a/src/imap/mod.rs b/src/imap/mod.rs
index 3bf9a706a..8fb864a6c 100644
--- a/src/imap/mod.rs
+++ b/src/imap/mod.rs
@@ -27,6 +27,7 @@ use crate::message::{self, update_server_uid};
 use crate::mimeparser;
 use crate::oauth2::dc_get_oauth2_access_token;
 use crate::param::Params;
+use crate::provider::get_provider_info;
 use crate::{scheduler::InterruptInfo, stock::StockMessage};
 
 mod client;
@@ -149,7 +150,7 @@ struct ImapConfig {
     pub imap_port: u16,
     pub imap_user: String,
     pub imap_pw: String,
-    pub certificate_checks: CertificateChecks,
+    pub strict_tls: bool,
     pub server_flags: usize,
     pub selected_folder: Option<String>,
     pub selected_mailbox: Option<Mailbox>,
@@ -169,7 +170,7 @@ impl Default for ImapConfig {
             imap_port: 0,
             imap_user: "".into(),
             imap_pw: "".into(),
-            certificate_checks: Default::default(),
+            strict_tls: false,
             server_flags: 0,
             selected_folder: None,
             selected_mailbox: None,
@@ -228,7 +229,7 @@ impl Imap {
                 match Client::connect_insecure((imap_server, imap_port)).await {
                     Ok(client) => {
                         if (server_flags & DC_LP_IMAP_SOCKET_STARTTLS) != 0 {
-                            client.secure(imap_server, config.certificate_checks).await
+                            client.secure(imap_server, config.strict_tls).await
                         } else {
                             Ok(client)
                         }
@@ -240,12 +241,8 @@ impl Imap {
                 let imap_server: &str = config.imap_server.as_ref();
                 let imap_port = config.imap_port;
 
-                Client::connect_secure(
-                    (imap_server, imap_port),
-                    imap_server,
-                    config.certificate_checks,
-                )
-                .await
+                Client::connect_secure((imap_server, imap_port), imap_server, config.strict_tls)
+                    .await
             };
 
         let login_res = match connection_res {
@@ -379,7 +376,15 @@ impl Imap {
             config.imap_port = imap_port;
             config.imap_user = imap_user.to_string();
             config.imap_pw = imap_pw.to_string();
-            config.certificate_checks = lp.imap_certificate_checks;
+            let provider = get_provider_info(&lp.addr);
+            config.strict_tls = match lp.imap_certificate_checks {
+                CertificateChecks::Automatic => {
+                    provider.map_or(false, |provider| provider.strict_tls)
+                }
+                CertificateChecks::Strict => true,
+                CertificateChecks::AcceptInvalidCertificates
+                | CertificateChecks::AcceptInvalidCertificates2 => false,
+            };
             config.server_flags = server_flags;
         }
 
diff --git a/src/login_param.rs b/src/login_param.rs
index 7309a90ad..01e66caa9 100644
--- a/src/login_param.rs
+++ b/src/login_param.rs
@@ -277,21 +277,15 @@ fn get_readable_flags(flags: i32) -> String {
     res
 }
 
-pub fn dc_build_tls(certificate_checks: CertificateChecks) -> async_native_tls::TlsConnector {
+pub fn dc_build_tls(strict_tls: bool) -> async_native_tls::TlsConnector {
     let tls_builder = async_native_tls::TlsConnector::new();
-    match certificate_checks {
-        CertificateChecks::Automatic => {
-            // Same as AcceptInvalidCertificates for now.
-            // TODO: use provider database when it becomes available
-            tls_builder
-                .danger_accept_invalid_hostnames(true)
-                .danger_accept_invalid_certs(true)
-        }
-        CertificateChecks::Strict => tls_builder,
-        CertificateChecks::AcceptInvalidCertificates
-        | CertificateChecks::AcceptInvalidCertificates2 => tls_builder
+
+    if strict_tls {
+        tls_builder
+    } else {
+        tls_builder
             .danger_accept_invalid_hostnames(true)
-            .danger_accept_invalid_certs(true),
+            .danger_accept_invalid_certs(true)
     }
 }
 
diff --git a/src/provider/data.rs b/src/provider/data.rs
index 3f5fbb058..f8abe83f4 100644
--- a/src/provider/data.rs
+++ b/src/provider/data.rs
@@ -19,6 +19,7 @@ lazy_static::lazy_static! {
             Server { protocol: SMTP, socket: STARTTLS, hostname: "newyear.aktivix.org", port: 25, username_pattern: EMAIL },
         ],
         config_defaults: None,
+        strict_tls: false,
     };
 
     // aol.md: aol.com
@@ -30,6 +31,7 @@ lazy_static::lazy_static! {
         server: vec![
         ],
         config_defaults: None,
+        strict_tls: false,
     };
 
     // autistici.org.md: autistici.org
@@ -43,6 +45,7 @@ lazy_static::lazy_static! {
             Server { protocol: SMTP, socket: SSL, hostname: "smtp.autistici.org", port: 465, username_pattern: EMAIL },
         ],
         config_defaults: None,
+        strict_tls: false,
     };
 
     // bluewin.ch.md: bluewin.ch
@@ -56,6 +59,21 @@ lazy_static::lazy_static! {
             Server { protocol: SMTP, socket: SSL, hostname: "smtpauths.bluewin.ch", port: 465, username_pattern: EMAIL },
         ],
         config_defaults: None,
+        strict_tls: false,
+    };
+
+    // chello.at.md: chello.at
+    static ref P_CHELLO_AT: Provider = Provider {
+        status: Status::OK,
+        before_login_hint: "",
+        after_login_hint: "",
+        overview_page: "https://providers.delta.chat/chello-at",
+        server: vec![
+            Server { protocol: IMAP, socket: SSL, hostname: "mail.mymagenta.at", port: 993, username_pattern: EMAIL },
+            Server { protocol: SMTP, socket: SSL, hostname: "mail.mymagenta.at", port: 465, username_pattern: EMAIL },
+        ],
+        config_defaults: None,
+        strict_tls: false,
     };
 
     // comcast.md: xfinity.com, comcast.net
@@ -65,7 +83,16 @@ lazy_static::lazy_static! {
     // - skipping provider with status OK and no special things to do
 
     // disroot.md: disroot.org
-    // - skipping provider with status OK and no special things to do
+    static ref P_DISROOT: Provider = Provider {
+        status: Status::OK,
+        before_login_hint: "",
+        after_login_hint: "",
+        overview_page: "https://providers.delta.chat/disroot",
+        server: vec![
+        ],
+        config_defaults: None,
+        strict_tls: true,
+    };
 
     // example.com.md: example.com, example.org
     static ref P_EXAMPLE_COM: Provider = Provider {
@@ -78,6 +105,7 @@ lazy_static::lazy_static! {
             Server { protocol: SMTP, socket: STARTTLS, hostname: "smtp.example.com", port: 1337, username_pattern: EMAIL },
         ],
         config_defaults: None,
+        strict_tls: false,
     };
 
     // fastmail.md: fastmail.com
@@ -89,6 +117,19 @@ lazy_static::lazy_static! {
         server: vec![
         ],
         config_defaults: None,
+        strict_tls: false,
+    };
+
+    // five.chat.md: five.chat
+    static ref P_FIVE_CHAT: Provider = Provider {
+        status: Status::OK,
+        before_login_hint: "",
+        after_login_hint: "",
+        overview_page: "https://providers.delta.chat/five-chat",
+        server: vec![
+        ],
+        config_defaults: None,
+        strict_tls: true,
     };
 
     // freenet.de.md: freenet.de
@@ -102,6 +143,7 @@ lazy_static::lazy_static! {
             Server { protocol: SMTP, socket: STARTTLS, hostname: "mx.freenet.de", port: 587, username_pattern: EMAIL },
         ],
         config_defaults: None,
+        strict_tls: false,
     };
 
     // gmail.md: gmail.com, googlemail.com
@@ -115,6 +157,7 @@ lazy_static::lazy_static! {
             Server { protocol: SMTP, socket: SSL, hostname: "smtp.gmail.com", port: 465, username_pattern: EMAIL },
         ],
         config_defaults: None,
+        strict_tls: true,
     };
 
     // gmx.net.md: gmx.net, gmx.de, gmx.at, gmx.ch, gmx.org, gmx.eu, gmx.info, gmx.biz, gmx.com
@@ -129,6 +172,7 @@ lazy_static::lazy_static! {
             Server { protocol: SMTP, socket: STARTTLS, hostname: "mail.gmx.net", port: 587, username_pattern: EMAIL },
         ],
         config_defaults: None,
+        strict_tls: false,
     };
 
     // i.ua.md: i.ua
@@ -145,6 +189,7 @@ lazy_static::lazy_static! {
             Server { protocol: SMTP, socket: STARTTLS, hostname: "smtp.mail.me.com", port: 587, username_pattern: EMAIL },
         ],
         config_defaults: None,
+        strict_tls: false,
     };
 
     // kolst.com.md: kolst.com
@@ -157,7 +202,16 @@ lazy_static::lazy_static! {
     // - skipping provider with status OK and no special things to do
 
     // mailbox.org.md: mailbox.org, secure.mailbox.org
-    // - skipping provider with status OK and no special things to do
+    static ref P_MAILBOX_ORG: Provider = Provider {
+        status: Status::OK,
+        before_login_hint: "",
+        after_login_hint: "",
+        overview_page: "https://providers.delta.chat/mailbox-org",
+        server: vec![
+        ],
+        config_defaults: None,
+        strict_tls: true,
+    };
 
     // nauta.cu.md: nauta.cu
     static ref P_NAUTA_CU: Provider = Provider {
@@ -178,6 +232,7 @@ lazy_static::lazy_static! {
             ConfigDefault { key: Config::E2eeEnabled, value: "0" },
             ConfigDefault { key: Config::MediaQuality, value: "1" },
         ]),
+        strict_tls: false,
     };
 
     // outlook.com.md: hotmail.com, outlook.com, office365.com, outlook.com.tr, live.com
@@ -191,9 +246,10 @@ lazy_static::lazy_static! {
             Server { protocol: SMTP, socket: STARTTLS, hostname: "smtp-mail.outlook.com", port: 587, username_pattern: EMAIL },
         ],
         config_defaults: None,
+        strict_tls: false,
     };
 
-    // posteo.md: posteo.de
+    // posteo.md: posteo.de, posteo.af, posteo.at, posteo.be, posteo.ch, posteo.cl, posteo.co, posteo.co.uk, posteo.com.br, posteo.cr, posteo.cz, posteo.dk, posteo.ee, posteo.es, posteo.eu, posteo.fi, posteo.gl, posteo.gr, posteo.hn, posteo.hr, posteo.hu, posteo.ie, posteo.in, posteo.is, posteo.jp, posteo.la, posteo.li, posteo.lt, posteo.lu, posteo.me, posteo.mx, posteo.my, posteo.net, posteo.nl, posteo.no, posteo.nz, posteo.org, posteo.pe, posteo.pl, posteo.pm, posteo.pt, posteo.ro, posteo.ru, posteo.se, posteo.sg, posteo.si, posteo.tn, posteo.uk, posteo.us
     static ref P_POSTEO: Provider = Provider {
         status: Status::OK,
         before_login_hint: "",
@@ -204,6 +260,7 @@ lazy_static::lazy_static! {
             Server { protocol: SMTP, socket: STARTTLS, hostname: "posteo.de", port: 587, username_pattern: EMAIL },
         ],
         config_defaults: None,
+        strict_tls: true,
     };
 
     // protonmail.md: protonmail.com, protonmail.ch
@@ -215,16 +272,35 @@ lazy_static::lazy_static! {
         server: vec![
         ],
         config_defaults: None,
+        strict_tls: false,
     };
 
     // riseup.net.md: riseup.net
-    // - skipping provider with status OK and no special things to do
+    static ref P_RISEUP_NET: Provider = Provider {
+        status: Status::OK,
+        before_login_hint: "",
+        after_login_hint: "",
+        overview_page: "https://providers.delta.chat/riseup-net",
+        server: vec![
+        ],
+        config_defaults: None,
+        strict_tls: true,
+    };
 
     // rogers.com.md: rogers.com
     // - skipping provider with status OK and no special things to do
 
     // systemli.org.md: systemli.org
-    // - skipping provider with status OK and no special things to do
+    static ref P_SYSTEMLI_ORG: Provider = Provider {
+        status: Status::OK,
+        before_login_hint: "",
+        after_login_hint: "",
+        overview_page: "https://providers.delta.chat/systemli-org",
+        server: vec![
+        ],
+        config_defaults: None,
+        strict_tls: true,
+    };
 
     // t-online.md: t-online.de, magenta.de
     static ref P_T_ONLINE: Provider = Provider {
@@ -235,6 +311,7 @@ lazy_static::lazy_static! {
         server: vec![
         ],
         config_defaults: None,
+        strict_tls: false,
     };
 
     // testrun.md: testrun.org
@@ -249,6 +326,7 @@ lazy_static::lazy_static! {
             Server { protocol: SMTP, socket: STARTTLS, hostname: "testrun.org", port: 587, username_pattern: EMAIL },
         ],
         config_defaults: None,
+        strict_tls: true,
     };
 
     // tiscali.it.md: tiscali.it
@@ -262,6 +340,7 @@ lazy_static::lazy_static! {
             Server { protocol: SMTP, socket: SSL, hostname: "smtp.tiscali.it", port: 465, username_pattern: EMAIL },
         ],
         config_defaults: None,
+        strict_tls: false,
     };
 
     // ukr.net.md: ukr.net
@@ -282,12 +361,13 @@ lazy_static::lazy_static! {
             Server { protocol: SMTP, socket: STARTTLS, hostname: "smtp.web.de", port: 587, username_pattern: EMAILLOCALPART },
         ],
         config_defaults: None,
+        strict_tls: false,
     };
 
     // yahoo.md: yahoo.com, yahoo.de, yahoo.it, yahoo.fr, yahoo.es, yahoo.se, yahoo.co.uk, yahoo.co.nz, yahoo.com.au, yahoo.com.ar, yahoo.com.br, yahoo.com.mx, ymail.com, rocketmail.com, yahoodns.net
     static ref P_YAHOO: Provider = Provider {
         status: Status::PREPARATION,
-        before_login_hint: "To use Delta Chat with your Yahoo email address you have to allow \"less secure apps\" in the Yahoo webinterface.",
+        before_login_hint: "To use Delta Chat with your Yahoo email address you have to create an \"App-Password\" in the account security screen.",
         after_login_hint: "",
         overview_page: "https://providers.delta.chat/yahoo",
         server: vec![
@@ -295,6 +375,7 @@ lazy_static::lazy_static! {
             Server { protocol: SMTP, socket: SSL, hostname: "smtp.mail.yahoo.com", port: 465, username_pattern: EMAIL },
         ],
         config_defaults: None,
+        strict_tls: false,
     };
 
     // yandex.ru.md: yandex.ru, yandex.com
@@ -306,6 +387,7 @@ lazy_static::lazy_static! {
         server: vec![
         ],
         config_defaults: None,
+        strict_tls: true,
     };
 
     // ziggo.nl.md: ziggo.nl
@@ -319,6 +401,7 @@ lazy_static::lazy_static! {
             Server { protocol: SMTP, socket: STARTTLS, hostname: "smtp.ziggo.nl", port: 587, username_pattern: EMAIL },
         ],
         config_defaults: None,
+        strict_tls: false,
     };
 
     pub static ref PROVIDER_DATA: HashMap<&'static str, &'static Provider> = [
@@ -326,9 +409,12 @@ lazy_static::lazy_static! {
         ("aol.com", &*P_AOL),
         ("autistici.org", &*P_AUTISTICI_ORG),
         ("bluewin.ch", &*P_BLUEWIN_CH),
+        ("chello.at", &*P_CHELLO_AT),
+        ("disroot.org", &*P_DISROOT),
         ("example.com", &*P_EXAMPLE_COM),
         ("example.org", &*P_EXAMPLE_COM),
         ("fastmail.com", &*P_FASTMAIL),
+        ("five.chat", &*P_FIVE_CHAT),
         ("freenet.de", &*P_FREENET_DE),
         ("gmail.com", &*P_GMAIL),
         ("googlemail.com", &*P_GMAIL),
@@ -344,6 +430,8 @@ lazy_static::lazy_static! {
         ("icloud.com", &*P_ICLOUD),
         ("me.com", &*P_ICLOUD),
         ("mac.com", &*P_ICLOUD),
+        ("mailbox.org", &*P_MAILBOX_ORG),
+        ("secure.mailbox.org", &*P_MAILBOX_ORG),
         ("nauta.cu", &*P_NAUTA_CU),
         ("hotmail.com", &*P_OUTLOOK_COM),
         ("outlook.com", &*P_OUTLOOK_COM),
@@ -351,8 +439,58 @@ lazy_static::lazy_static! {
         ("outlook.com.tr", &*P_OUTLOOK_COM),
         ("live.com", &*P_OUTLOOK_COM),
         ("posteo.de", &*P_POSTEO),
+        ("posteo.af", &*P_POSTEO),
+        ("posteo.at", &*P_POSTEO),
+        ("posteo.be", &*P_POSTEO),
+        ("posteo.ch", &*P_POSTEO),
+        ("posteo.cl", &*P_POSTEO),
+        ("posteo.co", &*P_POSTEO),
+        ("posteo.co.uk", &*P_POSTEO),
+        ("posteo.com.br", &*P_POSTEO),
+        ("posteo.cr", &*P_POSTEO),
+        ("posteo.cz", &*P_POSTEO),
+        ("posteo.dk", &*P_POSTEO),
+        ("posteo.ee", &*P_POSTEO),
+        ("posteo.es", &*P_POSTEO),
+        ("posteo.eu", &*P_POSTEO),
+        ("posteo.fi", &*P_POSTEO),
+        ("posteo.gl", &*P_POSTEO),
+        ("posteo.gr", &*P_POSTEO),
+        ("posteo.hn", &*P_POSTEO),
+        ("posteo.hr", &*P_POSTEO),
+        ("posteo.hu", &*P_POSTEO),
+        ("posteo.ie", &*P_POSTEO),
+        ("posteo.in", &*P_POSTEO),
+        ("posteo.is", &*P_POSTEO),
+        ("posteo.jp", &*P_POSTEO),
+        ("posteo.la", &*P_POSTEO),
+        ("posteo.li", &*P_POSTEO),
+        ("posteo.lt", &*P_POSTEO),
+        ("posteo.lu", &*P_POSTEO),
+        ("posteo.me", &*P_POSTEO),
+        ("posteo.mx", &*P_POSTEO),
+        ("posteo.my", &*P_POSTEO),
+        ("posteo.net", &*P_POSTEO),
+        ("posteo.nl", &*P_POSTEO),
+        ("posteo.no", &*P_POSTEO),
+        ("posteo.nz", &*P_POSTEO),
+        ("posteo.org", &*P_POSTEO),
+        ("posteo.pe", &*P_POSTEO),
+        ("posteo.pl", &*P_POSTEO),
+        ("posteo.pm", &*P_POSTEO),
+        ("posteo.pt", &*P_POSTEO),
+        ("posteo.ro", &*P_POSTEO),
+        ("posteo.ru", &*P_POSTEO),
+        ("posteo.se", &*P_POSTEO),
+        ("posteo.sg", &*P_POSTEO),
+        ("posteo.si", &*P_POSTEO),
+        ("posteo.tn", &*P_POSTEO),
+        ("posteo.uk", &*P_POSTEO),
+        ("posteo.us", &*P_POSTEO),
         ("protonmail.com", &*P_PROTONMAIL),
         ("protonmail.ch", &*P_PROTONMAIL),
+        ("riseup.net", &*P_RISEUP_NET),
+        ("systemli.org", &*P_SYSTEMLI_ORG),
         ("t-online.de", &*P_T_ONLINE),
         ("magenta.de", &*P_T_ONLINE),
         ("testrun.org", &*P_TESTRUN),
diff --git a/src/provider/mod.rs b/src/provider/mod.rs
index fc414968f..f74819180 100644
--- a/src/provider/mod.rs
+++ b/src/provider/mod.rs
@@ -72,6 +72,7 @@ pub struct Provider {
     pub overview_page: &'static str,
     pub server: Vec<Server>,
     pub config_defaults: Option<Vec<ConfigDefault>>,
+    pub strict_tls: bool,
 }
 
 impl Provider {
diff --git a/src/provider/update.py b/src/provider/update.py
index eb0a9e02b..60edeb238 100755
--- a/src/provider/update.py
+++ b/src/provider/update.py
@@ -100,6 +100,9 @@ def process_data(data, file):
 
     config_defaults = process_config_defaults(data)
 
+    strict_tls = data.get("strict_tls", False)
+    strict_tls = "true" if strict_tls else "false"
+
     provider = ""
     before_login_hint = cleanstr(data.get("before_login_hint", ""))
     after_login_hint = cleanstr(data.get("after_login_hint", ""))
@@ -111,6 +114,7 @@ def process_data(data, file):
         provider += "        overview_page: \"" + file2url(file) + "\",\n"
         provider += "        server: vec![\n" + server + "        ],\n"
         provider += "        config_defaults: " + config_defaults + ",\n"
+        provider += "        strict_tls: " + strict_tls + ",\n"
         provider += "    };\n\n"
     else:
         raise TypeError("SMTP and IMAP must be specified together or left out both")
@@ -121,7 +125,7 @@ def process_data(data, file):
     # finally, add the provider
     global out_all, out_domains
     out_all += "    // " + file[file.rindex("/")+1:] + ": " + comment.strip(", ") + "\n"
-    if status == "OK" and before_login_hint == "" and after_login_hint == "" and server == "" and config_defaults == "None":
+    if status == "OK" and before_login_hint == "" and after_login_hint == "" and server == "" and config_defaults == "None" and strict_tls == "false":
         out_all += "    // - skipping provider with status OK and no special things to do\n\n"
     else:
         out_all += provider
diff --git a/src/smtp/mod.rs b/src/smtp/mod.rs
index 3a4188d6a..3bde05730 100644
--- a/src/smtp/mod.rs
+++ b/src/smtp/mod.rs
@@ -10,8 +10,9 @@ use async_smtp::*;
 use crate::constants::*;
 use crate::context::Context;
 use crate::events::Event;
-use crate::login_param::{dc_build_tls, LoginParam};
+use crate::login_param::{dc_build_tls, CertificateChecks, LoginParam};
 use crate::oauth2::*;
+use crate::provider::get_provider_info;
 use crate::stock::StockMessage;
 
 /// SMTP write and read timeout in seconds.
@@ -113,7 +114,14 @@ impl Smtp {
         let domain = &lp.send_server;
         let port = lp.send_port as u16;
 
-        let tls_config = dc_build_tls(lp.smtp_certificate_checks);
+        let provider = get_provider_info(&lp.addr);
+        let strict_tls = match lp.smtp_certificate_checks {
+            CertificateChecks::Automatic => provider.map_or(false, |provider| provider.strict_tls),
+            CertificateChecks::Strict => true,
+            CertificateChecks::AcceptInvalidCertificates
+            | CertificateChecks::AcceptInvalidCertificates2 => false,
+        };
+        let tls_config = dc_build_tls(strict_tls);
         let tls_parameters = ClientTlsParameters::new(domain.to_string(), tls_config);
 
         let (creds, mechanism) = if 0 != lp.server_flags & (DC_LP_AUTH_OAUTH2 as i32) {