Oringinally, the headphones would connect then disconnect seconds later. I have tried unpairing and repairing, rebooting the headphones, and making sure the software is up to date. Currently, the iMac shows it is paired in the Bluetooth preference window but the Sound preference window can't make the connection. Any sugestions would be appreciated.
Thank you for reaching out to the community. Sorry to hear about the difficulty you are having with your headphones.
Just for troubleshooting purposes, can we try the headset with another device such as a tablet or smartphone?
Let's try removing the headset from your iMac, clearing the paired device list from the headset, and restart your computer. Please also confirm you have tried updating the Bluetooth drivers on your computer.
Can you try pairing with your iMac again and let us know how everything works out?