invalid datetime in attempt to set expires

[1925WilhelmAntonius]

Hallo, after upgrading our homepage from CMSms 1.12.2 to 2.2.11 I have a problem in the FrontEndUser administration.

A user property and a user group are created.

Trying to to create a user I get the the following error message:
„invalid datetime in attempt to set expires“

My versions:
CGExtensions: 1.64.8
CGSimplySmarty: 2.2.1
FrontEndUser: 3.1.4
News: 2.51.6
Galery: 2.3.3
PHP: 7.2.22

What can I do?