Cannot repair mail service for a domain: Invalid or unsupported Unicode character or escape sequence found in string

Symptoms

plesk repair mail command fails with the following error:

# plesk repair mail example.com

Repairing the mail server configuration
Reconfiguring the settings of domains: example.com ........ [OK]
Reconfiguring the mailboxes .....................................
[2016-09-13 15:56:14] ERR [util_exec] proc_close() failed ['/usr/local/psa/admin/bin/mailname_repair'] with exit code [1] [FAILED]
- mailname_repair failed: 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 2124, character '\\'.
Worker /usr/local/psa/admin/sbin/mailname_repair.worker failed
with exit status 1

Error messages: 0; Warnings: 0; Errors resolved: 0

exit status 1

Cause

NON-UTF symbols in auto-reply in one or several mailboxes. This is Plesk bug with ID #PPPM-4946 , that will be fixed in future Plesk updates.

Resolution

As workaround:

1. Log in to Plesk

2. Open Home > Domains > example.com > Mail and find all mailboxes with auto-reply enabled.

3. Disable autoreply for each mailbox via Home > Domains > example.com > Email address accounts > mailbox@example.com > Auto-reply - Uncheck the option Switch on auto-reply

4. Connect to the server via SSH and run the command:

   # plesk repair mail

5. Turn on autoreply for mailboxes, if needed via Home > Domains > example.com > Email address accounts > mailbox@example.com > Autoreply - Check the option Switch on auto-reply