I cloned a repo from GitLab this morning, made some changes, and was about to commit when I got this:

remote: HTTP Basic: Access denied
remote: You must use a personal access token with 'read_repository'
	or 'write_repository' scope for Git over HTTP.
remote: You can generate one at
	https://gitlab.com/-/profile/personal_access_tokens

Sure enough, listing the remote sources showed HTTPS not SSH:

$ git remote -v
==> origin https://gitlab.com/rubenerd/repo_name (fetch)
==> origin https://gitlab.com/rubenerd/repo_name (push)

So I changed:

$ git remote set-url origin git@gitlab.com:rubenerd/repo_name.git

Donezo.