I'm using a test number and when I make the API call to send messages, it returns a status code "200": "message status":"accepted", but it never gets delivered. I'm using templates that already have the accepted status.
The programming code I'm using was working correctly until two weeks ago, then suddenly messages stopped being received (only a few are delivered). My application is a vital tool that is monitoring and sending messages very constantly, and they are usually blocks of messages together. When it stopped working, I had no other option than to open a new application with a borrowed Facebook account, to use a test number while I solved the error, but the messages are still not delivered.
When I first started this new application, the first two messages were delivered to the five senders (with the test number) correctly, but they have already stopped being delivered. I need help, because monitoring messages are vital.

The "App Review" process requires registering your phone number using a verified certificate (see screenshot).

1. Obtain the phone certificate

I obtained the certificate through this link: WhatsApp Manager > Phone numbers
https://business.facebook.com/latest/whatsapp_manager/phone_numbers/?business_id=1234&asset_id=1224&nav_ref=whatsapp_manager&tab=phone-numbers&psp_linking_success=0&is_from_mbs=1

2. WhatsApp requires to register the phone using an /v1/account endpoint

The WhatsApp system requests that you send a POST request to the /v1/account endpoint, as described in the WhatsApp Business Platform > On-Premises API > Reference
https://developers.facebook.com/docs/whatsapp/on-premises/reference/account/

3. Attempt to call the /v1/account endpoint

I attempted to call the endpoint using this URL:
https://graph.facebook.com/v1/account
The body of the request follows the format defined in the API documentation 2.

Here is the body of the POST request:

POST /v1/account {     "cc": "COUNTRY_CODE",     "phone_number": "PHONE_NUMBER_WITHOUT_COUNTRY_CODE",     "method": "sms" or "voice",     "cert": "VERIFIED_NAME_CERT_IN_BASE64",     "pin": "EXISTING_6_DIGIT_PIN"  # required if two-step verification is enabled } 

4. Error message got after calling /v1/account endpoint

I get the follow error

{     "error": {         "message": "Unknown path components: /account",         "type": "OAuthException",         "code": 2500,         "fbtrace_id": "1234"     } } 

My application is using Twilio to deliver WhatsApp message. Would like to understand why messages using utility template were still being blocked from delivery by Meta due to error 63049 (i.e. Meta chose not to deliver this WhatsApp marketing message). From my understanding, this error should only occur when reaching Meta's unspecified limits about marketing template messages only

In Meta Developer, our WhatsApp app doesn't show anything—it displays a blank page and doesn't show the API setup and configuration. We've been experiencing this issue for 5 days.

I've been trying to access the Quickstart, API setup, and configuration menu in my WhatsApp Business app for some time now and all I get is a blank screen (attached). I've tried to remove cache and cookies, and I've also redone an account from scratch but the problem persists. It's been 4 days. How to solve this problem?