You can try this one liner change in /home/yellowtent/box/src/docker.js and then systemctl restart box. After that go to the Dashboard and Repair the app.
@girish Dear Girish, I applied this fix and now works again! Many thank's for patience!
I use the mobile app everyday as well and use port 443 to connect. I put a note in https://docs.cloudron.io/apps/emby/#apps . FWIW, I use the jellyfin app as well with my emby install and that works too. Jellyfin's chromecast feature is a bit buggy, so I cannot use it all the time.
I can run a test instance for you @girish on Azure with NVidia et al using the N series VMs if you like/need a tester. Couple different config options to play with. Just LMK