Meta says my number is not eligible for Coexistence. What now?

In short: Meta refuses numbers with too little recent activity on the WhatsApp Business app. Keep using the number normally and try again in a few days. Nothing was authorized, and the attempt cost nothing.

Why it happens

Meta checks the number inside its own connection window, before anything is authorized, and does not publish the threshold. In practice about 7 days of real use on the WhatsApp Business app has been enough, and a freshly registered or re-registered number starts from zero.

What to do

1. Keep using the number in the WhatsApp Business app, replying to a few contacts each day.
2. Make sure the app is on version 2.24.17 or newer.
3. Do not delete and re-register the number: that starts the count over.
4. Try again in a few days, from a computer.

Other refusals that look similar

• Number not found on the WhatsApp Business app: the number is on regular WhatsApp, was typed without the country code, or was moved to the API elsewhere.
• Number already registered: pick it from the list on Meta's phone number screen instead of typing it, and check Settings > Account > Business Platform in the WhatsApp Business app for a provider you no longer use. All the steps.
• Already shared with another partner: the number is still linked to a previous provider. In the WhatsApp Business app, open Settings > Account > Business Platform, disconnect it, wait 15 minutes and try again. All the steps.
• A security check about a new device or location: clear it at business.facebook.com in the same browser, then connect again. All the steps.
• This number can't be shared with this app: Meta does not say why, and several causes are known. What to check and how to ask Meta.

All the requirements are on What you need to connect.