| In our case the culprit was not restarting the Jenkins instance after the initial install of all the Blue Ocean plugins (including Autofavorite), which is not normally required when installing a new plugin. Every first build of a new branch/PR failed with this problem after that. Our solution was uninstalling every one of the Blue Ocean plugins (which was painful, given how many there are), restarting Jenkins to complete the uninstall, installing Blue Ocean plugins again, and restarting Jenkins again (the step we'd missed before). After that, it has worked perfectly. |