Account connection broken

I tried to import some of my GitHub repos to Bitbucket but I ended up at an endless spinning circle... When I tried to disconnect my GitHub account, I got an error saying that I have to set a password fist. I do have a password set and even changing it didn't work.

I then revoked access to Bitbucket in my GitHub account and got the error "We're having trouble connecting to Github " at the 'Connected Accounts' section. When I press the 'Reconnect' button, I can authorize Bitbucket as an Application at GitHub but when I press 'Authorize application' I get redirected to a 505 Bitbucket page.

Could it be because I changed my account name on GitHub recently?

Thanks in advance!