Make sure that the network your Proto M and iPhone are connected to have sufficient upload and download speed. We require a minimum of 15 MBPS and recommend 25 MBPS upload/download speed for Beaming from Beam location to location of the M. Run an internet speed test to test your connection.
In the Proto Beam application, go to Beam Settings and make sure that the Beam Quality is set to Full HD and not 4k.