AIRDROP PROBLEM SOLVED!!!!
Mac Book Pro (Retina mid 2015): El Captain OSx 10.11.3
iPhone 6 plus: iOS 9.2.1
My airdrop wasn't working at all before. And I tried a few suggestions posted around the web, I turned off the firewall, made both devices discoverable, played with bluetooth on both sides, nothing. Airdrop was not working whatsoever. Then I cam across MDaytona's suggestion above:
Just changed the name of your Mac Book to something else.
System preferences > Sharing
I changed both my computer's name, and I clicked on the edit button to change the name of the computer on the local network.
It worked!! but only after restarting the Mac!
MDaytona is right, for some reason updating the name of the mac triggers the airdrop connectivity to be updated/refreshed. I made a few quick tests and it seems to work without issues now, I don't even have to have airdrop open on both devices. It just works as you would expect.
In my case, the mac wasn't restored form time machine. Airdrop just never worked.
I can't believe Apple hasn't figured this out earlier.
I hope this helps all of you out there trying to sort this out!
P.S. My Bluetooth between the two devices is still not working, it wasn't working before this fix and it is not after. When I try to connect it says that "The device does not have the necessary services". Or if i try to connect my iphone to network it says "Network is unavailable. Make sure Network access is enabled."
So I would exclude Bluetooth playing any role in this fix.