May 20, 2020
I just had this exact same problem. "Oops! Something went wrong" would not go away. I restarted my phone, the app, my headphones, etc. Nothing would fix it. Finally, I went into my bluetooth settings on my phone and told it to forget "LE-Bose NC 700" and that fixed it! The next time I tried to add my headphones it went through the whole flow without another "Oops!".
Jun 5, 2020
Thanks for the tip! Going to iOS Settings -> Bluetooth -> Bose NC 700 -> Forget This Device fixed the problem for me and I was able to re-pair my headphones.