I’m stuck connecting my phone number to Meta’s WhatsApp Business API. The number keeps showing as “unregistered” when I try to generate an access token, so I can’t move past verification. Here’s what I need: • Diagnose why the number fails during the access-token step. • Walk me through—or directly handle—the correct sequence inside Meta Business Manager, Facebook Developer tools, and the Graph API. • Complete whatever is required so the number is fully verified, registered, and able to send and receive messages via the WhatsApp Cloud API. You should have hands-on experience with: • Meta Business verification flows • Phone-number onboarding for WhatsApp Business • Access-token generation and permission scopes • Troubleshooting unregistered or mismatched numbers Deliverable: a working phone number on my account with a valid, testable access token and clear notes so I can repeat the process for future numbers.