Airdrop not working -- just get broken blue circles
Hello - There must be a simple solution but I cannot seem to figure it out.
On my two Macbook Pro machines, I can open Airdrop, but all I get is the broken blue lines (with a pie-shape missing). Bluetooth is turned on, wi fi is turned on... so why is it not giving me a full circle icon for my computer?
I have tried dragging a file onto the broken blue lines but it doesn't work.
OSX is Sierra. MacBooks are a 2010 Macbook Air and a 2016 Macbook Pro.
Thanks for your help!
Airport Extreme-OTHER, Mac OS X (10.7.5), Netgear DG834 router