Error 500 when accessing a project through the Web console on gitlab hosted

Error 500 accessing project on hosted gitlab.com

In my company DecisionBrain,
We have created a project imported from bitbucket:
https://gitlab.com/decisionbrain/projects/db-gene

It was working fine.
This project was a test for the pipeline migration, when we are fine with the test we wanted to suppress this project in order to do the real migration (do a fresh import of the bitbucket repo).
I start by deleting the project (https://gitlab.com/decisionbrain/projects/db-gene) and because it still appears in the web console, click on import from bitbucket on this project.

Now each time I try to enter this project in the web console, I have a 500 error.

What I am seeing:

Help:
We workaround this solution by importing this project under another group, and it works well.
Now we would like to remove this old artifact, please delete this project for us, or help us to unlock this project so we can delete it by our own.

Thank you in advance,
Regards.

It was long but the issue solves by itself.
The project came back in a state where I can delete it after a big amount of time (days).