I just got a new bluetooth speaker, an Urbanears Stammen (concrete grey)
I can connect to it from my phone, using Bluetooth, and play back sound without problems. But I can't get my Windows 10 laptop (Dell XPS 15) to use it as a playback device.
I can connect and pair to the laptop without problems, as you can see in the screenshot below
It also shows up under bluetooth in the device manager. It's not listed under "Audio inputs and outputs" though, which I thought it should be, but I can see it under "Sound, video and game controllers".
But I can't select it as a playback device.
I found this relevant superuser question Windows 10 computer paired w/ bluetooth speaker, but doesn't send music to speaker and I tried the suggested steps listed there, but nothing helped.