Airplay stops streaming media when my Iphone 5s goes to sleep.

Airplay stops streaming media when my Iphone 5s goes to sleep. Im using Plexplayer. The streamer is AppleTv2 and it shows the welcome screen when the phone goes to sleep. Both the Plex player and the AppleTv is of no use to me like this. It worked fine before and I cant figure out what changed. I will not set my phone to "never go to sleep".