Fitz_Hoo is right! I just wanted to give a more detailed explanation that fix my issue. Essentially GitHub deprecated their password authentication recently (you can read more by clicking here).
Now instead of adding your username/email and password, you will login with your browser. The image below is the new interface. As Fitz_hoo mentions, you must update your Git to see the new changes!
If you are using Windows, you can simply use this command below to update your Git:
git update-git-for-windows