My IMAP connection is no more working

Symptoms

After an update, your IMAP account can no longer connect and shows this error:

This operation is only allowed using a successfully authenticated context.

Cause

Your mail server requires a secure connection, but the account is set up without SSL. Mail servers increasingly refuse unencrypted connections.

Solution

Enable the secure connection (SSL) in your account settings.

1. Click Your accounts, then edit the account that fails.
2. Go to step 3.
3. Click More options.
4. Select Use a secure connection (SSL).
5. Check the Server port. With SSL, IMAP usually uses port 993 (instead of 143).
6. Click Test connection, then save.
7. If it still doesn't work, please re-enter your password.