This morning one of my streams had no output. LMS and AmpliPro showed it as playing, but no output. I moved speakers to another AmpliPro output and the speakers work, but there is nothing from the other AmpliPro output. I deleted the stream and recreated, now it works.
Since I had to give up on Spotify I’ve been using LMS to play local files from USB. I saw AmpliPro has media support, but it’s early and missing features. Also LMS can do “group” playback which I like. The LMS UI is atrocious though.
While typing that last paragraph, the volume jumped to max out of nowhere, or at least very loud. It scared the hell out of me and took me a while to fumble to the LMS UI to turn it down. I absolutely can’t be having that happen! Since LMS controls the volume, I guess I need to stop using LMS. I was using only the Group Players plugin.
I’m willing to keep trying to use AmpliPro, but if I ultimately can’t get both the hardware and software to work reliably, then I’ll have to find another solution. 
However, right now without Spotify or LMS I don’t have a way to play my media.