iPhone 11pro not connecting to speaker

I have an iPhone 11 Pro and no matter what it’s not connecting my bowers and Wilkins formation flex speaker. My iPhone 7 connected fine and it worked fine. But I sold my iPhone 7 and got an 11 pro. Now it’s not connecting to the speaker. I need to say ahead that the speaker only works if there’s a 2.4ghz wifi connection. Which I have. Bowers and Wilkins has an app that I have to use to connect. But every time I try to connect. It says connection lost. I don’t know why. I’m not sure if it’s the wifi or Bluetooth that is causing this problem.