First:
・My Jenkins is working on docker container.
・GitLab is installed in "Redmine Certified by Bitnami" instance of AWS
(use port 80 for Redmine and 8888 for GitLab) .
Issue:
When I try
URL:http://JENKINS_URL/project/PROJECT_NAME on webhook,
I get this massage.

・I try also
https://JENKINS_USER_ID:JENKINS_API_TAKEN@JENKINS_URL/project/PROJECT_NAME,
but it did not work.
・Both checked and unchecked the "Enable SSL verification" did not work.
Version:
Is this error caused by wrong setting of Nginx?
Or related on other network connecting error?
Please give me some advice.
@asagi687 have you followed the directions at https://github.com/jenkinsci/gitlab-plugin#gitlab-to-jenkins-authentication? Does this user have Job/Build permissions in Jenkins? You can try enabling debug logging by following the directions here: https://github.com/jenkinsci/gitlab-plugin#getting-help and see if that helps show what the issue is.
Hi @omehegan I tried whatever you suggested but I am also getting the same error. I am running a Ubuntu VM with Jenkins instance in Azure.

@asagi687 have you followed the directions at https://github.com/jenkinsci/gitlab-plugin#gitlab-to-jenkins-authentication? Does this user have Job/Build permissions in Jenkins? You can try enabling debug logging by following the directions here: https://github.com/jenkinsci/gitlab-plugin#getting-help and see if that helps show what the issue is.
Thanks for your comment!
this solution served for me
https://github.com/jenkinsci/gitlab-plugin#gitlab-to-jenkins-authentication
Using in webhook:
https://USERID:APITOKEN@JENKINS_URL/project/YOUR_JOB
I got :
Hook executed successfully but returned HTTP 405 <html>
<head><title>405 Not Allowed</title></head>
<body>
<center><h1>405 Not Allowed</h1></center>
<hr><center>nginx/1.16.1</center>
</body>
</html>
Most helpful comment
@asagi687 have you followed the directions at https://github.com/jenkinsci/gitlab-plugin#gitlab-to-jenkins-authentication? Does this user have Job/Build permissions in Jenkins? You can try enabling debug logging by following the directions here: https://github.com/jenkinsci/gitlab-plugin#getting-help and see if that helps show what the issue is.