Collabora not working in app without port 80

Hello everybody,

I have a setup on docker with latest Nextcloud 21 + collabora + nginx as a reverse proxy.
Everything is working well on my computer or on firefox on my smartphone and with the app 3.15.1 in wifi but not in 4G

With the android app I can open nextcloud in wifi or 4G, but I cannot open document in collabora (it says it takes a long time and then timeout)

I spent 2-3 hours to figure out it was because I disable listening on port 80 in nginx. (it’s reproductile, I tried several time to add a listener and redirection on port 80 to make it works)

It seems like a bug for me, can someone try to reproduce it please?