I'm currently developing using the whatsapp business API and I'm using the test number provided by the API and it is working fine. I'm getting an error while adding a phone number to receive and send text messages and I would like to understand why...

I will provide the details below:

I already made the sms authentication, read the documentation to verify it and the phone number is being shown in the interface of the API. But when I try to use the phone number to send messages, I get an error saying that it is not available yet... I will provide some images of the error, hope it will be useful

When I add a phone number I must wait a short period of time to use the phone number or it is something that I'm not doing? Thanks guys for the support