Connecting to Smart tv via ethernet

The T-Mobile Wi-Fi works great in my house and my smart tv connects to it fine. However, when I began using Hulu live tv it won't show the live tv via Wi-Fi. I connected the T-Mobile internet box to my tv via Ethernet. The tv shows there is a wired connection but no network detected. No ip address shows up. 
Then I tried connecting from T-Mobile to my router/modem (not sure the technical term) that I was using when I had cable internet and then to the tv. Still no network detected. 
Anyone have any suggestions? Thanks!