The app is just a controller. It has no physical impact on hardware. 
You don’t mention what Sonos you actually have, and how everything is connected to the TV. 
 

Hello I have the era 300 .  All Bluetooth connected . I’m aware about the app .. and don’t really use it . When I contacted Sonia’s with regards with the issue of the volume cutting out randomly she said it was the app on my phone .  I followed all her guidelines but still having the same problem 
 

So your Era300 is connected to the TV by Bluetooth?

Can you go into your TV’s Bluetooth settings and ‘Forget device’ for the Era300 and set up the Bluetooth connection between them again. Re-establishing the connection might fix the issue.