UAR on Hololens 2 (Edge)

is it possible to get an example (such as [1]) working on Hololens 2 Edge?
After granting Zappar access to the camera I only see a white canvas and a DOMException: Could not starts video source caused by camera-source.js:6.

Basic WebXR samples [2] work without issues. I am also able to access the HL’s camera with WebRTC [3].

I know those cases are hardly comparable but maybe there is a way to get UAR to work on HL Edge as well.

[2] WebXR - Samples
[3] WebRTC samples