We've just purchased BT Sport and logged in using the app on our Samsung Smart TV. It buffers every 4 or 5 seconds, making it unwatchable. We watch sport regularly through Prime and Now TV, and don't have any problems at all.
Our speed is 7-8mbs download speed. I read somewhere that BT auto adjusts the stream quality to match your connection, but that doesn't seem to be happening.
Any ideas, or worth admitting defeat and perusing a refund?
There are other reports of problems with the BT Sport app on various, but not all, Samsung TV's. Maybe best to ask Samsung what this issue is.