Did Amazon Music work from Sonos before this new Mac? If so, why did you try to change your configuration? It is all stored in the speakers, there is no need to change anything just because you added a new Mac. Are you tryng to add the same account twice or something?

For some reason searching for anything in Amazon Music with the new mac came up with 0 results over and over so I removed the service to re-add it, hoping that would resolve the issue. Then I wasn’t able to re-add Amazon Music. I’ve finally got it added again today but still cannot search for music (on the new mac). I can still search for music using my phone and wife’s phone. I have a feeling it has something to do with the new M1 chip mac because some of my other apps aren’t working correctly either. 

Search on the desktop (Mac) works slightly differently to the mobile or tablet apps. In the tablet or mobile if you search then it searches everywhere. Whilst on the desktop app you have to select the service within which you want to search. The tick in the screenshot is where Sonos will search.

So in your case select Amazon Music and then choose you music or Amazon Music.

Hopefully this is your “issue”. It’s caught me out a few times too!

My new Macbook Pro M1 worked as soon as I switched on and then downloaded my old configuration from Apple Icloud   I did absolutely nothing to make it, or anything else, on the  macbook work - it just worked and is still working flawlessly.  

Ah ha, I realized in order to search Amazon Music, I had to select “Amazon Music” again after selecting it once. I did not realize this was a thing, and the new MacBook had switched it on me, defaulting it to search “My Music” within Amazon Music. Switching it back to Amazon Music > Amazon Music did the trick. I feel like the default should be to search Amazon Music and not My Music, but alas.

*Sigh*

Thanks for the help, all. I caught it before I saw his post, but Stuart_W was right!