ERROR: Connection dropped by IMAP server received when subscribing to folders

We receive the following message after trying to subscribe to folders.

ERROR: Connection dropped by IMAP server.
Query: SUBSCRIBE "INBOX.INBOX_Sent"

This happened to a client after trying to a client. We checked their quota, and temporarily set it to one gigabyte to see if it was a memory issue and it was not. Tried to restart courier-imap and this failed in fixing this issue. Not sure where to look and have searched these forums already.

 

1) Are you using a webmail client (i.e. SquirellMail, Horde, etc. )? If so, which one?

- Squirrel Mail

2) And/or are you trying to access the folders via Outlook, Thunderbird, Entourage, etc.?

This was in Squirrel Mail. The error occured in Squirrel mail when trying to subscribe to folders.

3) Does your cPanel account use mbox or maildir? If the latter, is this a recent conversion?

This uses maildir, conversion was performed a day or so ago.

 

Thank you.

I edited the address.

root@world [/backup]# tail -n 2000 /var/log/maillog | grep ACCOUNT_NAME
Nov 1 11:52:06 world imapd: LOGIN, user=ACCOUNT_NAME, ip=[::ffff:127.0.0.1], protocol=IMAP
Nov 1 11:52:06 world imapd: Failed to create cache file: maildir_lock (ACCOUNT_NAME)
Nov 1 11:52:06 world imapd: Failed to create cache file: maildir_lock (ACCOUNT_NAME)
Nov 1 11:52:07 world imapd: LOGOUT, user=ACCOUNT_NAME, ip=[::ffff:127.0.0.1], headers=0, body=0, time=1
Nov 1 11:52:58 world imapd: LOGIN, user=ACCOUNT_NAME, ip=[::ffff:127.0.0.1], protocol=IMAP

 

Thanks for your help.

The user went over their quota.

That's generally the first thing that I check.

 

The issue has been resolved already.

The user was way over his quota.

Once he raised his quota the error was no longer received.

Everything works fine now.