curl error 6: can't resolve host in UWP runtime

I'm developing a multiplayer game with unity 2019.4 and the HLAPI 1.0.6 package. Everything works fine for PC and MAC (IOS not tested), for Android, but not for UWP.
As soon as I build a version outside the editor (inside works fine), I get a curl error 6: cannot resolve host when I try to create or join a game via the matchmaker functionality. In the Visual Studio solution I see two projects for the HLAPI package, on for the runtime, another one for the unity editor. Obviously there are differences here.
I saw related issues for Hololens in the issue database, but these are supposed to be fixed in earlier versions.
Does anybody recognize this problem and guide me to a solution?

Thx

Christian

Did you enable internet capability in the manifest (or player settings)?

thx,
after enabling Internet Client in player settings->capabilities it works perfectly

Christian

Rosolved that too. Jist wanted to add that it's not enough to simply mark the InternetClient capability but it is also required to regenerate the UWP solution (e.g. clear the previous build folder or build to a new one). And then it regenerates the AppxManifest.xml adding the InternetClient capability

  </Applications>
  <Capabilities>
    <Capability Name="internetClient" />
  </Capabilities>
  <Extensions>

Maybbe it could be enough to simply edit this AppxManifest.xml manually