Can you confirm that the Sonos device is located within Spain and you aren’t using a VPN?

Have you added Apple music as a service within the Sonos App and linked the same Apple Music account when adding the Apple Music skill within the Alexa App?

If not please see this article:

https://support.apple.com/en-gb/119922#:~:text=Set%20up%20Apple%20Music%20as%20your%20default%20music%20service&text=Here's%20how.-,Open%20the%20Amazon%20Alexa%20app.,down%20and%20tap%20Music%20%26%20Podcasts.

If Yes, then please Disable the Sonos Skill within the Alexa App and then Re-Enable.

Re-enabled Sonos Skill in Alexa App and the problem have been fixed!! 
 

thanks!!