why my iptv hangs ??

hello. so in my tv i have fire tv stick 4k and chromecast 4k running GTV both hooked up.

i run iptv and have used all good apps namely tivimate, televizo, implayer, smarters etc etc

however i have this issue of buffering only on chromecast no matter what app i use. my wifi is 5ghz and is same for fire tv as well

on fire tv the same iptv in same apps works flawless with buggering.

same tv

same wifi

same apps

same iptv provider

whats the reason for chromecast to do that ????