Plex on Ipad and computer great, but not on smart tvs

Hi,

Ive just signed up to plex premium and very excited about getting it all set up, it seems fine on my desktop pc which has my media and also on my ipad but when trying to use my Smart TVs (brand new Samsung and 4 year old Hisense that has worked with Plex at a previous address)

My setup is a EE Router connected to TP Link Deco Mesh WiFi)

Ive tried to allow unsecure networks which hasn’t helped and still says offline or unteachable.

Ideas welcome, one tv is ethernet and one is wifi, dont quite understand how it can be router issue if the ipad works over wifi, I need a smarter mind to help.

Plex is a new install and version 1.23.2.4625

My time is valuable, so i bought a couple of 3rd gen google chromecasts rather than mess about with my router and loads of settings.