I think I have the same problem with my Amp2.
It is setup as HiFi Berry Amp2 on Max2play under the HiFiBerry menu and under Squeezelite in the advanced options it is set as „sysdefault – snd_rpi_hifiberry_dacplus, – Default Audio Device, CARD=sndrpihifiberry“
In Squeezebox (logitech media server) I can select the device and play music but I get no sound from the AMP2. I have another setup going using the Amp+ and this works perfectly.
One bit that does seem odd is that back in the Max2Play config under the Raspberry Settings, in the dropdown under where it says:
„The following DACs/AMPs are supported. Just choose the one that you want to enable and click save. After Reboot you may find more options (e.g. volume settings) for your selected soundcard on this page.“
There is not an option for the AMP2 listed only the HiFi Berry Digi/Digi+.
I do not have any other players installed on the devices. Been at this for 2 nights now and can’t think where I am going wrong.