If you are at a business you should have an access point or router that is capable of blocking specific devices from WAN access. But I would create a new segmented network, block that network from WAN access entirely, put it on its own VLAN, and then connect the TV to that network.
You can use your router or access point tools to check what address it’s trying to resolve and then set up a redirect to a device that can respond with a fake response.
If you are at a business you should have an access point or router that is capable of blocking specific devices from WAN access. But I would create a new segmented network, block that network from WAN access entirely, put it on its own VLAN, and then connect the TV to that network.
I’d assume it nags whenever it can’t connect to the home server, and just says “network”.
So when they go out of business any remaining units will nag forever.
You can use your router or access point tools to check what address it’s trying to resolve and then set up a redirect to a device that can respond with a fake response.