Unable to connect to Roku
I have a Roku Streaming Stick 4k which is one year old and an LG TV also one year old. All of a sudden I can no longer connect to Roku. The remote turns the TV on & off and volume works.  All I get on my TV is ROKU which fades in and out- the screen will go black, then “Roku”  comes back on, then screen goes black again. I cannot even get the Roku Home Screen. I have unplugged the Roku unit from the outlet and removed the streaming stick.  I have tried resetting the remote.  I have three other Roku devices (all much older than this unit) and they are all working fine.   When I am watching tv (using the LG apps), “ROKU OTT”is showing in the upper right hand corner.   Everything was working fine until three days ago. 
What do I need to do to fix this?