GitLab merge request blocked with pipeline must succeed, but no pipeline is set up

Question

New to GitLab. I’m trying to merge a branch into a dev branch in a repo, however, the MR is blocked with the following message. However, this repo does not have a pipeline set up (screenshot). Plus, all my MR has been ok until this point. I don’t recall changing any git workflow. Any suggestion or idea on how to resolve this? Googling and ChatGPT haven’t helped much.

I've tried with other branch, they all have the same issue: "Merge blocked: pipeline must succeed. Push a commit that fixes the failure or learn about other solutions."