register wont work with docker container

[DasHund007]

Describe the bug
my register button isnt working on the dashboard of it

Expected behavior
That the button works and redirects me to taskcafe.DOMAIN/register

Additional context
the thing is, the button wont work but if i change the url to taskcafe.DOMAIN/register then it works and i can register normally.
even on my local adress [192.168.1.209], it wont work. so i dont get the problem