Git (GitLab) - Merge Fails - Trying instructions for "Check out, review, merge locally"

should help you out (I'm assuming before you start that git status is clean, so as not to risk losing any local changes.)
Since you're created a temporary branch anyway, why don't you just use git merge othercommit to merge in the other commit? Your working tree and index will be updated with the results of the merge, of course - it'll create a new commit, but if you don't like that you can just checkout your original branch to get back. If you want to make additional changes to fix up the results of the merge, that should really be in additional commit on top of the merge anyway.

git merge --no-commit othercommit

 git merge --squash othercommit

this one helps. If you do a git pull, the default merge message will include a reference to the upstream repo and the branch being fetched then merged (like github.com:foo/bar).
If you do a git merge, the default merge message will reference the upstream branch name (like origin/master)

hope this fix your issue Use the API
An example merge request would look like this:

To fix the issue you can do A pre-receive hook will run a script before acting on a git push
This error is saying that something in that script has gone wrong. You'll need to speak to the admin/owner of your git repo to ask them to help you with this as they will be able to see what went wrong.

This might help you There is no difference between PRs and MRs. The terminology "Pull request" is a reference to how git is used for example in kernel development. Say you are a developer, and I am the maintainer. For you to get changes incorporate, you would generate a diff patch and email it to me, so that I can review it, and request that I pull those changes from your repository if I think they are suitable. Hence "pull request", and the git command git pull-request.
A merge request is a reframing of this process. This is a result of the fact that we're not really asking for someone to pull from our repository, but rather asking that our changes be merged to the develop/master branch, often from a branch of the same repository. Hence, gitlab phrases the same process "merge request" rather than "pull request".