I have the same problems you guys have with MLB.TV on my brand-new 49" LG smart TV. I am shocked that a 2016 model would have so much trouble with the ubiquitous MLB.TV app. As others have noted, Netflix and Amazon work fine.
I can stream games for three or four minutes before the MLB.TV app crashes and the TV abruptly restarts. Sometimes the image freezes and stutters before it crashes. I have enough bandwidth and a high enough upload speed, based on my recent system tests.
I successfully streamed one game: the Marlins-Mets game from Monday, Aug. 29. In the words of the MLB.TV troubleshooting page, I "power cycled" my router and TV beforehand and the stream worked. Subsequent efforts to power cycle—turn everything off and then back on, basically—have failed. Help.