Does the same window pop up when you connect to your second H9 in the app?
We do know connection to multiple H9s is not as robust on Mac as on iOS devices. We’ve heard from our users that there are 2 workarounds. Also please put your H9s as close to your mac as possbile.
1. Trash the Bluetooth preferences and restart the Mac:
Go to /Library/Preferences/ and delete ~/Library/Preferences/ByHost
Upon restarting and opening the Bluetooth System Preferences, you will have to wait for the H9 to be recognized and then re-enter the PIN.
2. Hold down option-shift and click on the Bluetooth icon in the task bar. You'll now see a "Debug" sub menu. Click "Reset the Bluetooth Module" and then try connecting via the H9 control app.
If this doesn't help, you may need to consider using a USB cable to connect to the second H9.
