An error occurred when using cPanel Roundcube Webmail

User Issue:

Occasionally users of the Roundcube webmail program report that the following error message displayed when attempting to access a folder in webmail:

An error occurred! Server error! (OK)


When reading the error log at:

  • When Roundcube is using MySQL for its database backend:
    • /var/cpanel/roundcube/log/errors
  • When Roundcube is using SQLite for its database backend:
    • - cPanel versions prior to 78: /home/$username/tmp/errors
    • - cPanel versions 78+: /home/$username/logs/roundcube/errors.log
  • When PHP-FPM for cPanel services is enabled:
    • /home/$username/logs/.php.error.log

The following error entry will possibly be displayed:

Unexpected condition from IMAP server, closed or corrupt connection to IMAP. Possible mailbox corruption.

As stated, the above error message indicates a potentially corrupt index file.


Dovecot uses the index files to make the reading of mailboxes a lot faster and this file will be in the created for each separate mailbox. If the index files are missing, Dovecot will create them automatically when the mailbox is opened. Which means that we can fix this issue using the file manager built into cPanel.

Firstly, ask the user to logout of all webmail sessions, then when you have opened the File Manager navigate the /mail/ directory then look for the domain and user folders for the account that is having trouble. i.e. /home/<username>/mail/<domain name>/<email account name>/

Find the dovecot.index file and rename it to dovecot.index.bak

Note: It may be necessary to complete this activity in additional folders, specific to the account (such as .Trash, .Sent, etc).

When the user next logs in the Index files should be recreated and the issue resolved.


  • Roundcube, Cpanel, Email
  • 1 Users Found This Useful
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