After doing a git pull is it possible you have an error because your Git Token is not valid anymore, here is an exemple:
# git pull remote: HTTP Basic: Access denied fatal: Authentication failed for 'https://gitlab-ci-token:YOURTOKEN@gitlab.com/YOURPROJECT.git/'
In order to do the git pull we want to use our credential with the LOGIN / PASSWORD that we use to access GitLab.
Solution 1 : Git pull one time with login (temporary)
# git pull https://gitlab.com/YOURPROJECT.git
Solution 2 : Change the origin URL to HTTPS (permanent)
# git remote set-url origin https://gitlab.com/YOURPROJECT.git # git pull
It will ask your login and password for the git pull and will not use the git token anymore.