The problem was I already had another github account that I normally pushed to. So when I wanted to push to my new github account I got following error.
error: The requested URL returned error: 403 Forbidden while accessing https://github.com/github-username/github-repository-name.git/info/refs
To fix it I had to find a way to enforce a new password prompt.
First I checked which url was configured:
git config -l | grep url
which gave me following output:
to enforce now a new password prompt I had to change the
git remote set-url origin "https://firstname.lastname@example.org/github-username/github-repository-name.git"
When I tried to push again I was able to type in a password and push to the new github repo.