I have found with many 3rd party services that are linked to hardware or another service, most the time if you unlink/deauthorize them entirely... restart device... relink/enable the App/Service/Skill it seems to take care of it.
Is Amazon music working otherwise? (like through your smartphone app or on the web). It sounds like it's needing something on your Amazon account side.
Amazon music is working perfectly I'm listening to Amazon music right now, I have emailed Amazon music as well but I probably won't hear anything till Monday