Constantly disconnecting when screen is off

Recently started having an issue with playback when screen is off. Everything was working fine for years. I have the paid version of the app for about 3 years now but all of a sudden the station disconnects about 20 

seconds after phone screen goes off regardless of the station. It was using android stream engine and as above has been working fine for ages. When it disconnects, it will occasionally come back after around 15 seconds or so and then repeat... but usually ends up just playing the 'connection lost' knocking sound over and over and doesn't recover. I switched over to FFmpeg and it still disconnects but it recovers again after a few seconds and then disconnect and reconnect every 5 - 10 seconds.  I don't have 
power saving on or any other apps or features that close or limit background apps and/or data.... please help as I can no longer use my favourite app!