i dont have a solution for this; but it turned up on the parabola bug tracker some months ago, conflated with other similar issues, which affected icecat and parabola's iceweasel, probably since v81 - i dont believe that the problem existed when iceweasel was v78, so it is probably not the browser configuration that changed; but something gitlab.com changed recently
there seems to be multiple reasons why some websites dont work - one of them is the "enhanced tracking protection", another is geo-location - relaxing those settings, did not make gitlab.com work though there are multiple tickets on the gitlab bug tracker, which seem to be the same problem - several suggest that it is related to cookie expiration; but nothing indicated a solution i discovered that i could make gitlab,com work with iceweasel, by deleting the profile under ~/.mozilla/; but that trick did not work for icecat - i still dont know why that website rejects icecat - other instances of the gitlab software work as expected - changing the user-agent does not help either
