I'm experiencing an error during WhatsApp setup in Meta for Developers. When I select my phone number in Step 1, I get the error 'Got unexpected null or undefined'. Could you please help me resolve this issue?

Error validating access token: The application does not belong to system user's businessor its aggregators's business
"error": {
"message": "Error validating access token: The application does not belong to system user's businessor its aggregators's business",
"type": "OAuthException",
"code": 190,
"error_subcode": 465,
"fbtrace_id": "AwdeeckPQClEJZ817B1FMvg"
}

When adding new phone number to application for testing, this error shows up

I'm encountering an issue while setting up the WhatsApp API. Specifically, when I try to verify my WhatsApp number on the setup page, I receive the following error: Got unexpected null or undefined
Here are the steps I followed and the details of my setup:
WhatsApp API Setup: Followed the official documentation to set up the WhatsApp Business API.
Adding Phone Number: Navigated to the WhatsApp API setup page to add and verify my phone number. Entered the phone number in the required format.
Error Encountered: Upon submitting the phone number for verification, the system returns the error: Got unexpected null or undefined.

I'm developing an application similar to Confirmafy that uses the WhatsApp Business API to send messages to users. According to WhatsApp's documentation, message templates need to be pre-approved, and line breaks are not allowed within variables.

However, I've noticed that Confirmafy allows users to edit the message body, including adding line breaks, and the message is sent instantly without any apparent approval process. Here’s an example of how the message configuration looks in Confirmafy

In this configuration, I can insert line breaks and any text, and the message is delivered instantly via WhatsApp. This behavior seems to contradict WhatsApp's official documentation.

How does Confirmafy manage to send messages with line breaks in variables without needing pre-approval from WhatsApp? Is there a specific API endpoint or method that bypasses the template approval process? Are there any exceptions or special permissions required to achieve this functionality?

I already talked to Twilio and Meta support and they can´t help me. Someone know hoy can I do this? Thanks