Git PullRequest job failed. Couldn’t find any revision to build. Verify the repository and branch configuration for this job

I spent a long time on this. The above comment “if I leave this field blank” worked like a charm. In SCM:
1) select Git
2) Name: origin
3) Refspec: +refs/pull/*:refs/remotes/origin/pr/*
4) Branches to build : leave blank

This solved the above error.