Check your Wifi speed - If you experience buffering then run a speed test to make sure your internet is fast enough for streaming. Use a search engine and type in "internet speed test" and you will be presented with multiple options.
Improve your signal strength - Move your router away from walls or add a Wi-Fi booster. Also do not overload your network with too many other connected devices.
Restart everything - Unplug your router, modem, and streaming player, then wait 30 seconds and plug them back in.