Webmail or mail client does not show emails when a Plesk mailbox is not empty

Symptom

• When logging in to webmail or a mail client, the email list does not show up. Instead, one of the following error messages appears:

  • in Horde:

    PLESK_ERROR: could not open mail inbox

  • in Roundcube:

    PLESK_ERROR: Server Error: STATUS: Internal error occurred.

• One of the following error messages appears in /var/log/maillog:

  PLESK_INFO: dovecot: service=pop3, [email protected], ip=[]. Error: Index is read-only, can’t write-lock /var/qmail/mailnames/example.com/john_doe/Maildir/dovecot.index.log

  ---

  PLESK_INFO: dovecot: service=lda, [email protected], ip=[]. Error: sieve: failed to open logfile (LOGGING TO STDERR): open(/var/qmail/mailnames/example.com/john_doe/.dovecot.sieve.log) failed: Permission denied (euid=30(popuser) egid=31(popuser) UNIX perms appear ok (ACL/MAC wrong?))

  ---

  PLESK_INFO: Error: open(/var/qmail/mailnames/example.com/john_doe/Maildir/dovecot-uidlist) failed: Permission denied Aug 4 16:47:26 cloud1 dovecot: service=lda, [email protected], ip=[]. msgid=<[email protected]>: save failed to INBOX: Internal error occurred. Refer to server logfor more information.

• If the mailbox is set up in new a mail client, POP3 authorization fails.

Cause

Incorrect ownership on Dovecot files: The owner/group should be popuser:popuser

Resolution

1. Connect to the Plesk server via SSH.

2. Change owner and group to popuser:popuser for all Dovecot files that have incorrect ownership:

   # find /var/qmail/mailnames/ -name dovecot* -exec chown popuser:popuser {} ;

3. If this does not help, run:

   # chown popuser:popuser -R /var/qmail/mailnames/