Also seeing this issue with a server hosted on my local network.
If I go to an HTML page in the deo browser and click a direct video link, I get black screen with loading dots that never loads.
If I have the server generate me a DeoVR JSON file, the exact same links do work when clicked using the Deo JSON navigator.
I'm thinking this is more likely a DeoVR issue than a Quest OS issue 'since the video files work just fine through the JSON viewer.
While you're at it, can you make the DeoVR JSON viewer thumbnails work over http? The only way I can get them to display is if I give it an HTTPS link to an image file.