502 Error after Installation with Plesk


I have installed Gitlab on my own Server following a tutorial I found here: https://www.jonasjuffinger.com/2017/03/26/gitlab-with-plesk-and-lets-encrypt/

After I have setup all like it is described there and I navigate to the Domain, I will get an 502 Error from Gitlab. So I looked in the log files and found the following error in the production.log:

Started GET "/" for at 2018-09-12 11:04:11 +0200
Processing by RootController#index as HTML
Redirected to http://example.org/users/si...
Filter chain halted as :redirect_unlogged_user rendered or redirected
Completed 302 Found in 6ms (ActiveRecord: 0.0ms | Elasticsearch: 0.0ms)

Is it possible that this is the Problem? I don’t have an idea why there is standing: example.org -> in the gitlab.rb it is set to my domain.

Best greetings,