git - GitHub authentication failing over https, returning wrong email address

Question

Initiating a push or any other action with GitHub from the command line (over https, not ssh) that calls for the username and password not only fails but, when it does, it returns

Username for 'https://github.com': username
Password for 'https://username@github.com': 
remote: Invalid username or password.
fatal: Authentication failed for 'https://github.com/username/repository.git/'

I do not have an @github.com address. The password and username are correct.

I know I could switch to SSH and use keys but that doesn't answer why the authentication is failing over https.

Answer 1

GitHub's support determined the root of the issue right away: Two-factor authorization.

To use GitHub over the shell with https, create an OAuth token. As the page notes, I did have to remove my username and password credentials from Keychain but with osx-keychain in place, the token is stored as the password and things work exactly as they would over https without two-factor authorization in place.