This folder is empty

There are no branches found that contain buildable projects. Jenkins automatically builds and manages projects in branches that contain recognizable projects. Pipeline Branch projects support building branches within a repository containing a pipeline script. Per default it uses a file named Jenkinsfile in the root directory. This file should contain a valid Jenkins Pipeline. See also: Creating Multibranch Projects.

Configure the project for a buildable repository or re-index branches if the repository has since been configured.