I have a Dell XPS 9550 laptop with Windows 10, which uses the Dell Wireless 1830 Wifi + Bluetooth card. My bluetooth mouse connected and worked fine. I tried to connect a Plantronics Backbeat 505 bluetooth headphones to the laptop, it would pair but not connect. After much trial & error the solution is this:
And this worked! Hurray!
Update 1: The bluetooth headphones are still working but the audio is a bit choppy. I don’t have a solution for that yet.