Did you have seen something like this before?
No, I've never faced with such a problem.
If I got the solution, then I will write you here again
Please let us know if you got some news.
Merry Christmas Guys,
I was able to solve the problem, but I don’t know the root cause.
Finally something was wrong with the po-file.
It has accepted the translation after I delete the files via Loco Translate. So I generate a new translation and selected the Wordpress German Language. After this it works now.
Maybe the file was already faulty before installing Loco or Loco installed something faulty.
But at this point I’m happy that it is working now.
Merry Christmas Forronix,
Yes, Loco does some strange cache of PO/MO files in /languages/ directory of /wp-content/. Sometimes you need totally remove the plugin po/mo files from that /wp-content/languages/plugins/ directory to reset the translation cache.