Hi I’m using GSE iptv but when I cast it only casts the sound not the picture, I have tried numerous apps and they either only do this or keep crashing

Is there something I’m doing wrong as GSE iptv works spot on on my phone but I want it on the big screen. There’s a few paid apps Ive not tried but am reluctant as having so much bad luck with the free ones

any help is appreciated thank you