Google indexes several projects under wrong domain

Hi there,

few weeks ago we found weird behavior of our domain in google search index. It seems that Google somehow indexes several pages (projects) under our domain (see Links normally return 404. We have nothing to do with these projects. Two years ago we were running Gitlab Pages for few days under this domain as an informational site during the maintanence of our servers. Now Gitlab pages are shut down. That’s the only connection between Gitlab and this domain. We have removed these links from Google search console and even cache but with no results. Links are re-indexed repeatedly from unknown reasons.

Does anybody know how could it have happened and how to solve this issue?

Thanks in advace.