Before you begin, please test your microphone and camera here. This will allow you to diagnose if there is a problem and where it is!
If you or another user's audio and/or video cuts out after a few seconds (10s, 20s or 30s) after the call starts, we have seen that firewall settings at the location you or the other user is at does not allow certain audio / video traffic to pass through. If this happens, please read this article about firewall and proxy requirements for using Remo.co and this one on how to troubleshoot firewall issues