I'm trying to import an existing private GitHub repository into BitBucket but I come up on the following error each time: 
Upon reviewing the forums here, it seems the correct solution for clearing the error is to ensure GitHub credentials are correct, but when I logged out and back into GitHub, despite using the very same credentials to try and import the repo seconds later on BitBucket, I still get the above error.
My next thought was perhaps I needed to generate a token on GitHub or something, but I'm presently unable to locate a place on BitBucket to use it, so whether it's this or something else, any help would be appreciated. Thank you!