Add custom library from Ochestrator Error Root element

Hey everyone,

I created a library and published it to the orchestrator. When I want to install the package in a project I get an error saying that the Root element is missing. See below image.

Before you can install a package you have to add a new source. For url I took the orchestrator url but without any user/password or tenantid, f.e.:

Can anyone give advise on how to solve this Root element missing problem?

I already spent hours searching for a solution.