I recently had a problem with git credentials on Windows and a message like “git clone fatal: Authentication failed for…” Git did not work because the old password was set. In order for git to work again, I had to change the password in Windows settings.
To fix this, go to the following path:
Control Panel\User Accounts\Credential Manager
And more specifically:
Control Panel → User Accounts → Credential Manager → Windows Credentials
→ click on your git credentials → click Edit → and you can change password there

I updated my password and git started working again.