Video streaming from a server

Hey everyone,

In my app I'm using a video player component to stream a mp4 video from my server, i'm trying to render it on a cube - which works in the unity editor (version 2019.2.0f1) but when building to my device I get nothing.
I tried giving internet/local network permissions (in player settings and permission requester for the LAN)
any idea what could go wrong here?

Thank you