Occasionally, a phone number may show one of two particular statuses that are related to quality and messaging limits: Flagged and Restricted.
Flagged: This is a warned state. When the quality rating reaches a low (red) state, the phone number is moved to a Flagged status.
Restricted: Phone numbers that reach their messaging limit are moved to a Restricted state. During a Restricted state, the number will be unable to send any notification messages until the 24-hour window for sending messages is reset. They can still respond to any messages initiated by users.
The Quality Rating is based on user feedback and we are not able to see exactly the details.
To maintain high quality:
- Make sure messages follow the WhatsApp Business Policy.
- Only send messages to users who have opted into receiving messages from your business.
- Make the messages highly personalized and useful to users. Avoid sending open-ended welcome or introductory messages.
- Be mindful of messaging frequency; avoid sending customers too many messages a day. Be thoughtful of informational messages, optimizing for content and length
You can wait for 24hours since you got flagged status to improve the quality rating, then your number will return to connected status.
For more detail information you can check these link: https://developers.facebook.com/docs/whatsapp/api/rate-limits#quality