got same error....

My Context: 1. We are a tech provider integrating with the WhatsApp Business API.

1. Required Permissions: whatsapp_business_management (advanced) whatsapp_business_messaging (standard)

3.After onboarding a new phone number, we follow all the steps outlined in the documentation.

4.Issue: When attempting to send messages, we receive the following error: “(#33) You do not have the necessary permissions required to send messages on behalf of this WhatsApp Business Account.” However, the messaging works if I manually generate and use a system-user token for previously onboarded customers, rather than the delegated token obtained by exchanging the code for a token.

New Problem: During the Facebook login for onboarding, I encounter a white screen after selecting a phone number, preventing me from completing the process and retrieving a token. I suspect this may be related to a rejected request to upgrade whatsapp_messaging to advanced permissions, as functionality stopped working after that.

It's incredibly frustrating that there’s no support contact for assistance in resolving these issues.