Hi ​@taruru 

Welcome to the Sonos Community.

Your Japanese Amazon account will already use the local servers for Alexa - you’ll likely only see amazon.com mentioned at the sign-in page for your account when adding Alexa to your Sonos system. When utilising Alexa, your connections will be redirected to the local, Japanese servers.

I assume you are able to speak in Japanese to Alexa without issue? It should be the case - I have checked, and your location is already set to Japan. If so, all is well.

I hope this helps.

Hi Corry P.

Thank you reply.

Currently, My sonos one started working without any problems. 
Thank you so much.

Best regards Taruru.