Users are not able to log into mailboxes: Invalid or unsupported Unicode character or escape sequence found in string

Symptoms

• Users are not able to log into mailboxes and the following records can be found in the file
/var/log/maillog:    

  plesk courier-imaps: LOGIN FAILED, [email protected], ip=[::ffff:203.0.113.2]

  ---

  CONFIG_TEXT: dovecot_authdb_plesk[9898]: No such user ‘[email protected]‘ in mail authorization database 

• A domain does not exist in the output of the command
/usr/local/psa/admin/sbin/mail_auth_view
(or the output is empty at all without
grep):     

  # /usr/local/psa/admin/sbin/mail_auth_view | grep example.com
  # (empty output)

• Manual execution of the utility
mail_auth_dump
(
/usr/lib64/plesk-9.0/remote_mail_restore/mail_auth_dump
on RHEL-based operating systems,
/usr/lib/plesk-9.0/remote_mail_restore/mail_auth_dump
on Debian and Ubuntu) with the Plesk debug logging enabled fails with the following error:

  # /usr/lib/plesk-9.0/remote_mail_restore/mail_auth_dump
  ……….
  DEBUG [util_exec] [07d041579abfc778c97734f8eb0d4318-0] Finished in 0.0293s, Error code: 1, stdout: , stderr: /opt/psa/admin/bin/mail_auth_dump.worker[18105]: Input parse error: Invalid or unsupported Unicode character or escape sequence found in string. UTF8 encoded characters and ‘u’ escape sequences are not supported. Error occured at offset 51062, character ”.
  ERR [util_exec] proc_close() failed [‘/opt/psa/admin/bin/mail_auth_dump.worker’ ‘–start’ ‘–finish’] with exit code [1]

Cause

The password of one of the mail accounts contains unsupported symbols like ä, ö, ü, symbols like “♥”, or random sequences with leading “u”.

This repair tool behavior is confirmed as Plesk bug with ID PPPM-10902, which is planned to be fixed in future Plesk updates.

Resolution

1. Enable Plesk debug logging (without enabling
show.sql_query).

2. Connect to the server via SSH

3. Execute the utility
mail_auth_dump :

   RPM-based systems (CentOS, RHEL):

   # /usr/lib64/plesk-9.0/remote_mail_restore/mail_auth_dump

   APT-based (Debian, Ubuntu)

   # /usr/lib/plesk-9.0/remote_mail_restore/mail_auth_dump

4. In the output find the passwords with
u
sequence.

5. Log in to Plesk

6. Go to Domains > example.com > Email addresses and change the password for the found mail accounts.

7. Execute the command to repair mail authorization database:

   # /usr/local/psa/admin/sbin/mchk –with-spam