Source branch develop or target branch develop is not allowed

Issue

Context

• Gitlab plugin version: 1.5.13
• Gitlab version: 12.3.2
• Jenkins version: 2.198
• Job type: Pipeline
• Gitlab webhook: http://jenkins_user:jenkins_token@jenkins_ip/project/my_pipeline
• Gitlab webhook properties: {"push_events": true, "push_events_branch_filter": "develop"}

Logs & Traces

Gitlab plugin log: Source branch develop or target branch develop is not allowed

Problem description

• what were you doing: simple push
• what was expected: job was triggered
• what occurred finally: job was not triggered, got line Source branch develop or target branch develop is not allowed

What does it mean?

Unsure if you've found the solution to this - but I have had the same error message and it turned out that the branch we specified in the 'Allowed branches' section was in lowercase so Jenkins believed it to be a different branch than it was looking for.

@yetanothern did you get around the issue?

I have the same problem on same version of the plugin. We even allowed "All" branches, but still got the error saying "Source branch or target branch is not allowed."