Video/audio works but audio streaming will not

I can watch netflix or dvd movie and the audio and video work perfectly. I can play a CD in the dvd player and it works (with the "DVD" background/start screen on the TV). My wireless connection to the internet is at the top of the scale.

When I try to stream audio with iHeart Radio app (which has worked perfectly until now) I get a "Network Disconnected" message on the screen. When I click the "Network Setup" box under the error message, I can see that the wireless network IS connected at maximum signal strength. I also tried the TuneIn app and that will not work either (playback error?).

Not sure if there is a way to "reset" the TV, but I did unplug it for a minute and plug it back in -- same issue.

I don't watch a lot of TV, prefer to just have music playing while I work. Any ideas on what could be wrong?

Vizio 50'' 1080p Smart LED HDTV D50-D1

Thanks.

Kevin