itunes remote cannot find music library

I have iTunes library on both a Mac-Mini and a Win10 desktop. When I tried to use the REMOTE app to control the iTunes playlist on my iPhone, the apps said that there was no library linked. If I used the iPads, they could locate the library and control the music. The Apple TV had no problem locating the library on both computers. It just happened recently. I wonder if there is any recent change in the iPhone app that screws things up.