Merge Request Message: Rebase failed. Please rebase locally

Hello, I am trying to do a GitLab merge request.

I executed the following three commands twice in two different GitLab repositories. I used these Git Bash commands: git add fileX, git commit –m “commentX”, and git push. Where “X” is replace by “1” or “2”. One file named file1 is in C:\GIT\Test1. Another file is in C:\GIT\Test2. File1 is in one repository and file2 is in a completely separate repository. Both files were required to do a single feature change.
When I pressed the submit merge request button, I get an error that says the following: Rebase failed. Please rebase locally.

I have only one merge request.

Questions: What do I do to complete the merge request? Specifically, what command(s) do I enter to complete the merge request? Should I do more than one merge request?