Assuming you are live streaming over the Internet, my first test in this circumstance would be to check your actual Internet speed against what you “should” be getting according to your ISP. Tools like Speedtest are a good guide, as well as checking that someone else in your house is not hogging bandwidth by gaming or streaming at the same time!
Also, your ISP has probably suggested this already but having your router close to the TV or wired directly via an Ethernet connection rather than using WiFi can often eliminate issues.
Do you get the same buffering issues if you use your live TV service on a different device other than your TV? Could you try out the Hulu app on your phone or a laptop device? If you see the same amount of buffering there, we can rule out the TVs being the problem. Let me know if that's possible to try.