from the jenkins.log and $JENKINS_HOME/logs/jenkins.branch.MultiBranchProject.log

I can confirm the Gitlab server did send the push event and the jenkins server did receive the request

In the jenkins.log I can see the received  push events as follows:

2019-12-11 08:53:38.415+0000 [id=498] INFO o.g.api.webhook.WebHookManager#handleRequest: handleEvent: X-Gitlab-Event=Push Hook
2019-12-11 08:53:38.418+0000 [id=498] INFO i.j.p.g.GitLabWebHookListener#onPushEvent: PUSH EVENT
2019-12-11 08:53:38.419+0000 [id=498] INFO i.j.p.g.GitLabWebHookListener#onPushEvent: {..............etc

but no futher action about this trigger event

In the jenkins.branch.MultiBranchProject.log we may find the reason:

[Wed Dec 11 16:53:38 CST 2019] Received Push event to branch master in project xxx/yyy UPDATED event from 172.24.22.100 ⇒ http://172.24.31.106:8080/gitlab-webhook/post with timestamp Wed Dec 11 16:53:38 CST 2019
[Wed Dec 11 16:53:38 CST 2019] Finished processing Push event to branch master in project xxx/yyyy UPDATED event from 172.24.22.100 ⇒ http://172.24.31.106:8080/gitlab-webhook/post with timestamp Wed Dec 11 16:53:38 CST 2019. Matched 0.

what does the matched 0 mean ? It works fine when the result is "Matched 1" , but it just seems out of control and wired……