Connection dropped by IMAP server : When you are trying to login to email account in Roundcube Webmail client.

You may fix the issue by follow the steps below:

If you are using Roundecube check the following logs :

# tail -50 /var/cpanel/roundcube/log/errors

1. Try to restart the IMAP service

# /etc/init.d/courier-imap restart

2. Try to update the courier imap server

# /scripts/courierup –force

3. If the issue still not solve, run the command below to fix the permission for mail directory

chown -R USERNAME:mail /home/USERNAME/mail/
chown -R USERNAME:mail /homeUSERNAME//etc/

Where USERNAME is his cPanel username