Symptoms

plesk repair mail example.com command fails with the following error:

[root@plesk ~]# 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

Hieroglyphs in auto-reply in one or several mailboxes. This is Plesk internal issue with ID #PPPM-4946 , that will be fixed in future Plesk updates.

Workaround

Not to use hieroglyphs in subject and body of auto-reply messages.