Since the update of OJS to 3.1.2.1, OJS, if I want to reach the archive, throws an HTTP code 500 that the request could not be processed. There is nothing in the errorlog about this call, so I have no idea where this error occurs.
Now my question is whether this problem is already known and if so how I solve it.
The problem was the bootstrap3 plugin which was still running on an old version, an update to the new version solved the problem.