AirPlay not casting to Samsung TV

hard to say maybe

1. your tv needs a firmware upgrade, that is usually something one handle in it's settings
2. your tv and the device you attempt to airplay from are not present on the same network as in it does not work across the internet and if your router are not bridging wired, wifi2.4Ghz and wifi5Ghz and the 2 devices are present on different ones it would not work

but it's been a while since I attempted to airplay to my LG tv which also support it, heck it's even been awhile since I airplayed to my appletv box which is the main way I use my tv