Airdrop is working only 'one-way'

After a long quest I finally found the solution. Even with Firewall off it still didn't work.

So these are the steps that worked for me:

1. Go to "Security & Privacy" and select "Firewall"
2. "Click the lock to make changes"
3. Turn On Firewall if it wasn't yet on
4. Click "Firewall Options"
5. Make sure "Block all incoming connections" is not selected
6. Click the '+' sign
7. You get the list of applications, now search for "Bluetooth"
8. Select "Bluetooth File Exchange.app"
9. Click "Add"
10. Click "OK"

It should now work

Good luck !