Easily fix problem with Facetime log in

Recently, Facetime on my work laptop stopped working properly. Even with the correct ID and password, the app would "verify" my account but then refuse to activate Facetime. Instead I would get this error:

The registering device does not have appropriate credentials

Thanks to this post:

http://porkrind.org/missives/imessage-on-mac-os-x-not-working/

I learned that a simple "killall imagent" command in the terminal would restore Facetime functionality!

Yay, internet.