Fire stick app remote play no good

Server Version#: latest
Player Version#: latest on fire stick 4k max

Remote play on a firestick 4k max is rubbish. I can’t watch half the films on my server, if I’m remote, just buffers and never starts. I can watch the same content locally (on the same firestick) and I can watch the same content on my phone. Also a few adjustments on the TV installed app (in my son’s flat) and same content plays fine, but not on his fire stick plugged into the same tv. Why is the fire stick app so bad for remote play