airplay radio

I'm running iTunes 12.1.2.27 on a Mac Pro/Yosemite.

Suddenly, after working perfectly forever, radio streaming drops out after about 5 minutes. This happens through AirPlay to a stereo system or locally through the computer's speaker system.

The streaming will continue playing only if I use the stream available through the Radio tab in iTunes. Unfortunately, the AirPlay button disappears and is completely unavailable when streamed in this fashion.

PLEASE: HOW TO FIX!??!

• Why does radio streaming drop out??

• Where does the AirPlay go when streaming from the Radio tab???