So it doesn't seem to be fully down, but currently I get lots of 500s from gitlab.com - I am not sure if this is related, but it happens more often, if I am in "Private Browsing" mode (Firefox).
GitLab Employee here, this link might help provide some more details into days you're experiencing more/fewer 500s. You can always check the status page for the current status, but I find the history page to be useful for a broader picture of operations. https://status.gitlab.com/pages/history/5b36dc6502d06804c083...