When a file needs to be removed from history (credential file maybe?) completely.
Some steps need to be undertaken.
This command could take a long time if the repository is large.
Replace path_to_file to mach your file(s) using a wildcard or not.
git filter-branch --force --index-filter \
'git rm --cached --ignore-unmatch path_to_file' \
--prune-empty --tag-name-filter cat -- --all
Since it seems the repository is diverted from the repository remote it must be forced to replace.
git push --all --force
When the remote is located on GitLab and is a Protected branch this may needs
to be removed before it can be forced pushed.
Go to GitLab project "Settings" → "Repository" → "Expand" on "Protected branches".
To bring other repositories up-to-date execute the following commands:
git fetch origin master && git reset --hard FETCH_HEAD
Optionaly:
git clean -df