I have had the roku for a while now and at first the app worked great and I had basically no issues with it, until a few months ago, now the app won't even find my tv even if I enter the ip address shown, I also connected to the same wifi and it still didn't work, can anyone help me?
This sounds like a security setting in your WiFi router has been activated. Most have a setting that can block wireless devices from seeing each other, or anything else on the local network. Sometimes these are labeled as a guest network, or even just a setting within the full network.
These settings are in the router, but it's hard to say exactly where they are and how they're labeled. It might be device security or some such. It should be found somewhere in the radio settings, perhaps on the security page, perhaps elsewhere.
Dan Ultra (4640), Ultra (4670), Ultra (4800), Premiere (3920), Insignia 720p Roku TV, Sharp 4K Roku TV, Nvidia Shield, Windows 10 Pro x64 running Serviio and Plex on a wired Gigabit network.