Step #1. Exit any app or System preference that is running on Mac and which was trying to establish a connection with Bluetooth.
Step #2. In OS X Finder, press Command+Shift+G.
Step #3. It will launch “Go to Folder” and over there, you type/Library/Preferences/.
Step #4. Search for the file with an extension of “com.apple.Bluetooth.plist” and delete it. If there are other files with the same extension, delete them too.
Step #5. Return to desktop and click on the Apple menu.
Step #6. Select Shut Down.
Step #7. After some time, restart your Mac and re-sync your Bluetooth device.
What this does is, it creates a new .plist file for Bluetooth configuration.
Hopefully, this should fix Bluetooth connectivity issues on your Mac.