GitLab Runner failing to register after migration to new cluster
It looks like you have restored data and configuration from the previous cluster, however you are missing the secrets on the new cluster. Here you can find a procedure, what should you do, when the secrets are lost. You can also find there:
In cases like CI/CD variables and runner authentication, you can experience unexpected behaviors, such as:
- Stuck jobs.
- 500 errors. #you got this error
See also similar problems:
- Internal Server Error 500 while accessing $GITLAB/admin/runners
- gitlab 500 errors in the admin area
- gitlab-runner status 500 internal server error