ntozier Thanks for your help, but i already did your step, and this is my problem.
The reset email the customer receive isn't the same in your path. In the User/Template directory is the template for the password reset, But it's the wrong one.
That's the part i don't unterstand, because the reset email for Users/Customers is in this path.
"This template defines the email sent to Clients who select the Forgot My Password link on the Client Log In page."
osTicket does not send this exact email, it is almost the same but there is a broken link, and other small things.
The problem is that the email is translated into german correctly (which means we must have edited it somewhere).
but new changes in the template password reset doesn't change anything here either.
What I also notice is that the email is the only one that doesn't have a subject.