Connect bluetooth earbuds in Mojave failing
I tried a PRAM Reset and it seemed to work for me. Other things you can try are


Check your system log
tail -f /private/var/log/system.log
If you see something like the following in your log, then likely the PRAM reset will help


com.apple.xpc.launchd[1] (com.apple.preference.sound.remoteservice[4642]): Service exited due to SIGKILL | sent by com.apple.preference.sound.remot[4642]



Also try the following


sudo mv /Library/Audio/Plug-Ins/HAL/BluetoothAudioPlugin.driver ~/Desktop
Restart
sudo cp -R ~/Desktop/BluetoothAudioPlugin.driver /Library/Audio/Plug-Ins/HAL/