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manage the webhook fields and be sure you are subscribed to the following: account_review_update, account_update, message_template_status_update, messages, phone_number_name_update, phone_number_quality_update
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Add apps app to your Business Manager
now you have to add the app you’ve just created to your Business Manager.
you can follow this guide Add apps to your Business Manager to help you in the process
in your Business Manager, under Accounts, click Apps
click the blue Add drop-down menu
select Connect an app ID to add your app
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