Hi @Col28, welcome to the Sonos Community!
You shouldn’t need the Alexa app open to control your Sonos with Alexa, and I’m not sure why it only works that way. I would recommend following the steps in our support article for Alexa commands not working on Sonos.
I can’t find anything that relating to your issue, but it sounds like it could be a problem with the Alexa skill. Try disabling and re-enabling the skill by going to More →Skills & Games → Your Skills → Sonos → Disable Skill, then Enable Skill.
If the above steps don’t resolve this issue for you, I would suggest reaching out to our support team for further assistance.
I hope this helps!
I have 2 Amazon accounts and it turned out that I had the wrong Amazon Alexa log in. Thanks for your reply
