apple tv smart tv online but movie won't play

don't believe appletv+ works in webbrowsers on smart tv's only the apple tv app works on smart tv's

smart tv browsers don't really support the various plugins

these are the non appletv box devices which support appletv app which support appletv+

https://www.apple.com/apple-tv-app/devices/

Welcome to the Apple community.

I'm afraid you will need to give us a little bit more information about your problem if we are to help you.