iPad pro external keyboard stopped working

Hi there, Tingalpa!
Thanks for reaching out to the Apple Support Communities! It sounds like you are having an issue with your external keyboard not working with your iPad Pro and I’m happy to help! Pleas check out this article with steps to follow to Use your Smart Keyboard with iPad Pro. Specifically:

Get help

If your iPad Pro doesn't detect your Smart Keyboard or you see an "Accessory not supported" alert on your iPad Pro, make sure there's no debris or plastic covering on the Smart Connector pins on the keyboard or the Smart Connector on the iPad Pro. Also, try these steps:

1. Make sure that your iPad Pro and Smart Keyboard are in the Type position and that you have the latest version of iOS.
2. Remove the Smart Keyboard from your iPad Pro.
3. Restart your iPad Pro.
4. Reconnect the Smart Keyboard.