runner registration returns unauthorized

I tried to install gitlab-ci on my server (Ubuntu) today and followed the pipeline.

Now I face following problem:

root@censored:/home/censored/playground/server-test# gitlab-runner register
Running in system-mode.                            
                                                   
Please enter the gitlab-ci coordinator URL (e.g. https://gitlab.com/):
https://gitlab.censored.net/ci
Please enter the gitlab-ci token for this runner:
censored                                                         
Please enter the gitlab-ci description for this runner:
[censored]: 
Please enter the gitlab-ci tags for this runner (comma separated):

Whether to lock Runner to current project [true/false]:
[false]: 
ERROR: Registering runner... failed                 runner=censored status=401 Unauthorized
PANIC: Failed to register this runner. Perhaps you are having network problems

I can't find whats wrong. The gitlab-ci token i used is from

https://gitlab.censored.net/admin/runners