I’m having some trouble getting Max2Play to work properly with an AMP2. I have installed M2P, configured it to my network via WiFi, downloaded the HiFiBerry plugin and selected the AMP2, installed Squeezebox/LMS, and activated the Squeezelite and Airplay. I can see the device from my phone and can connect, but the audio ’stutters‘ and ’skips‘ terribly. I do have other Pi players on my network (Volumio) and can successfully stream to them, so I don’t think it’s the local network.
Please try disabling built-in audio in the Raspberry Settings, rebooting, setting hw:0 instead of hw:1 in the advanced settings of Squeezelite and Shairport and add -C 5 at the end (Command Line Options). Also, make sure that both players have different outputs selected.