Keypad in Facetime Calls on Mac

Howdy, guys!

Does anyone know how to make the keypad work on a facetime call when you're on the Mac? Like, when you have an automated system and need to input information? It used to work just fine for me, but ever since I upgraded to the last OS x (before Mojave), it hasn't. I've tried looking up the issue on Google with little luck.

Thanks in advance! :)