Twilio exception: A 'from' phone number is required

I’ve just set up a Twilio account and am using a Twilio number for SMS notifications.
Twilio account in Gateway is showing “active”.
Twilio Notification Profile in Gateway is showing “active”.
I can do a successful test message from twilio.com.
When triggering a notification event within Ignition, it goes through the pipeline, then throws an exception in the logs:

com.twilio.exception.ApiException: A ‘From’ phone number is required.

Does anyone that is familiar with recent Twilio setups have any idea why I might be getting that?
My understanding is that the ‘from’ phone number is entirely in the twilio.com configuration. I’ve looked through everything and can’t see why it wouldn’t be using the phone number I set up.

When you configure the Notification Block in the Designer there should be a drop down where you have to select a From Number to use. It will enumerate the numbers available on that Twilio account.

There it is! I hadn’t even noticed that.
Thanks for the help, @Kevin.Herron! Works like a charm. :+1: