Improved error messages

FAQ.md

@@ -712,6 +712,10 @@ The error *... Read timed out ...* means that the email server is not responding
 The error *... Failed to load IMAP envelope ...* is caused by a bug in the IMAP server of your provider.
 One or more messages could not be retrieved due to an unrecoverable error in the IMAP protocol.
 
+The error *Account not found* means that a previously selected Gmail account was not found anymore, see also [this FAQ](#user-content-faq136).
+
+The error *No token on refresh* means that no token was returned on refreshing the authentication of Gmail account, see also [this FAQ](#user-content-faq136).
+
 See [here](https://linux.die.net/man/3/connect) for what error codes like EHOSTUNREACH and ETIMEDOUT mean.
 
 Possible causes are:

app/src/main/java/eu/faircode/email/MailService.java

@@ -199,13 +199,13 @@ public class MailService implements AutoCloseable {
                             am.invalidateAuthToken(type, password);
                             String token = am.blockingGetAuthToken(account, getAuthTokenType(type), true);
                             if (token == null)
-                                throw new IllegalArgumentException("no token");
+                                throw new IllegalArgumentException("No token on refresh");
 
                             _connect(context, host, port, user, token);
                             return token;
                         }
 
-                    throw new IllegalArgumentException("no account");
+                    throw new IllegalArgumentException("Account not found");
                 } catch (Throwable ex1) {
                     Log.e(ex1);
                     throw ex;