I had experience with receiving message “ It’s connected to another device”.
I am using Samsung S7 Edge all the time. But lately whenever I tried to turn on using Osmo, this message appear.
I turned off all mobile devices near my Samsung, this message still exist.
I had both DJI Go and DJI Go4 installed onto the same mobile.
I deleted the DJIGo4,and the problem is solved.
Hope it will help.

Thanks for your sharing. Glad you find the solution. You can ask for our help, if you get a new problem.