Error during backup: actual configuration

[zentyalhk]

Hello,

I get an error when backup actual configuration:

Some error has happened in Zentyal:
malformed UTF-8 character in JSON string, at character offset 109 (before "\x{722}ertragung von...")

I guess it's a german so called umlaut, perhaps it should spell "Übertragung von.."
But my problem is i couldn't find WHERE this string occur to change it.

Where do I get more information about it from.
No module name is given, unfortunately...
 
What module configuration?
What Logfile?
What else?

thanks.