All users unable to git clone or push. Fails with "fatal: Authentication failed for"

[Robert du Toit]

Just recently started running into this issue on our local Bitbucket server instance. None of our users are able to clone/pull from any of our repositories. It pops up an Atlassian authentication dialog which does not authenticate the user correctly resulting in a "fatal: Authentication failed for" error. Following the "Can't log in?" button on this login screen directs us to the Bitbucket cloud login, which makes no sense as this is our own Bitbucket server instance. 

Neither SSH or HTTPS works. Not in Visual Studio, Sourcetree or git console either. The only way we have somehow been able to clone any repository is via Github's import repository option, which was successful in importing our repository.

All the users are able to successfully log into bitbucket via the web interface. They are able to create branches, commit code and create pull requests from here. 

Any assistance with solving this issue would be greatly appreciated. 

[Aidan Dauphin]

I am having this exact error, was this ever resolved?