Connection dropped by IMAP server. Query: LOGOUT

Hi everyone,

This past Sunday my host was attacked due to a SolusVM exploit and my VPS was wiped out. After my host reloaded the server and all its VPS containers, including mine, my websites were all up.

However, I just realized that no users of any websites can log onto Squirrel Mail.
Everyone is getting the error:

Code:

Connection dropped by IMAP server.
Query: LOGOUT

I checked the mail error log and found the following:

Code:

Jun 19 00:47:20 mydomain dovecot: imap-login: Aborted login (auth failed, 1 attempts): user=<shirley>, method=PLAIN, rip=::1, lip=::1, secured
Jun 19 00:47:33 mydomain dovecot: auth: Error: BUG: Authentication client sent unknown handshake command: REQUEST?2588540929?24320?1?4aa6b9a34443ab6b49f1eccb0f01d5dc
Jun 19 00:47:33 mydomain dovecot: imap: Error: Authentication server didn't send valid SPID as expected: MECH#011PLAIN#011plaintext
Jun 19 00:47:33 mydomain dovecot: imap: Error: Disconnected from auth server, aborting (client-pid=24320 client-id=1)
Jun 19 00:47:33 mydomain dovecot: imap-login: Internal login failure (pid=24320 id=1) (auth failed, 1 attempts): user=<shirley@mydomain.com>, method=PLAIN, rip=::1, lip=::1, mpid=24321, secured

Can someone please point me at the right direction to fix this?

Thank you very much in advance!