Need help with Whatsapp Cloud app

Hello,

I have almost integrated Rocket.Chat with WhatsApp Business through the Facebook app. The only part I am stuck on is figuring out where to add the WhatsApp number in Rocket.Chat.

Currently, when I send messages to the WhatsApp number, I receive the following in the app logs. While I can see the messages, they are not yet pushed to Rocket.Chat.

"{\"stack\":\"Error: Error! The Phone number 2132132132 is not registered on Rocket.Chat. Please register it first before sending messages.\\n    at Vo.processChange (app.js:73:11305)\\n    at runMicrotasks (<anonymous>)\\n    at processTicksAndRejections (internal/process/task_queues.js:95:5)\\n    at Vo.post (app.js:73:10883)\",\"message\":\"Error! The Phone number 2132132132 is not registered on Rocket.Chat. Please register it first before sending messages.\"}"

And the debug message is:

 "incoming's post was unsuccessful."

Docs followed: https://docs.rocket.chat/extend-rocket.chat-capabilities/rocket.chat-marketplace/rocket.chat-public-apps-guides/omnichannel-apps/whatsapp-cloud-app

Any help and direction would be appreciated.