Not connected to SES, Help

I everyone,

I am trying to use the xr simulator for quicker iteration on my mixed reality app. Unfortunately the xr simulator always shows "Not connected to SES". 
The synthetic environment server is running (I changed the registry entry to make the window appear too hence it should be very obvious it is running, see screenshot). I do not know why the connection between the two might not work.

Unity 6000.0.49f1, XR Simulator 77 

Does anyone know what could be wrong?

thanks in advance

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I think I figured it out. The SES connection only works when the pass-through component (for example found on the building block) is present in the scene. It does not seem to work with the open xr implementation of passthrough.