Hi folks,
Spammers have been abusing GitHub OAuth to create accounts on
gitlab.haskell.org and post spam.
Due to team resources, the only good way to stop spammers right now is to manually approve each new user. GitHub OAuth defeats that by automatically approving new users.
So, sadly, I have disabled GitHub OAuth for the time being. If you used it to sign up and have trouble logging in now, one of us admins can help you out.
-Bryan