I purchased the Echo Plus in April, which overall works just great. No problem playing Amazon Music or my playlists on request.
On Prime Day I bought a UE Megaboom portable speaker which works with Alexa. When I connect this to my phone on Bluetooth the UE app shows Alexa as connected and I can speak to Alexa via the UE speaker.
However, if I ask her to play any music she replies "Your Amazon Music marketplace is not configured correctly for this device". Amazon Music is set as the default music source.
If I connect the speaker to Alexa as a bluetooth device I can't speak to Alexa via the speaker, although if I ask her through the Echo Plus then Amazon Music plays happily on the UE speaker.
Spent what seems like hours going through the settings in the Alexa, Amazon Music and Megaboom apps but can't find anything that helps. I've also reset everything and set it all up again (more than once).
I've had an email conversation with UE customer care, but they are just telling me things I've already tried.
Any ideas on how I can get Alexa to play Amazon Music when the speaker is connected as an Alexa device (which means my phone has to be connected to the speaker via Bluetooth)?
I think you are trying to do something that is not intended. If you pair a bluetooth speaker with an alexa device (you can only pair one at a tjme) then if you ask the alexa device to play it will play via the paired speaker (and disable the alexa's internal speaker) but will not work if you talk to paired speaker.
Unfortunately using any bluetooth speaker disconnects the internal speaker so can't be used as an extension speaker with both playing, I tried numerous ways to see if there was a way round this but could not.