We updated recently from version 1.5.1 to 1.5.7 of the GitLab Branch Source plugin and since then it is not possible to connect to our internal GitLab anymore.

We get this error message:

PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target

Because this is an internal service, we are using self signed certificates which may cause this issue.

In the past this worked perfect but now the plugin is completely unusable for us because there is no option to ignore such certificate issues.

Attached you find the complete stack trace of the error.

I check the modifications that where done in the plugin since version 1.5.1 and it seems that the change in file

 src/main/java/io/jenkins/plugins/gitlabbranchsource/GitLabHookCreator.java:204

in the commit "JENKINS-62375 Fix/secret token (#91)" from May 31, 2020 is the root cause.

I think a possible solution could be to add an option to disable the SSL verification for such situations.