Updated FAQ

FAQ.md

@@ -1005,7 +1005,8 @@ Possible causes are:
 
 * A firewall or router is blocking connections to the server
 * The host name or port number is invalid
-* The are problems with the internet connection
+* There are problems with the internet connection
+* There are problems with resolving domain names (Yandex: try to disable private DNS in the Android settings)
 * The email server is refusing to accept (external) connections
 * The email server is refusing to accept a message, for example because it is too large or contains unacceptable links
 * There are too many connections to the server, see also the next question