Submit Facebook App Review
Submit an app review to activate "Start Verification" button for Facebook Business Verification
If the "Start Verification" button is stay grey after creating a app under Facebook Developer, you might have to submit an app review on Facebook for Developers to activate the button.
First, you need login to Facebook for Developer, then go to App Review > Requests through the left panel.
You will need to request permission for the app review. Click "Request Permissions or Features".
Search "pages_show_list" permissions on the search bar and click "Request".
You will then be directed to answer some questions and provide information to process.
It's not necessary for your app review to go through. These steps are only required so you can access the business verification step.
Provide information for "Complete App Verification" and "Requested Permission and Features" as required:
For Complete App Verification, you may follow the below selection.
For Requested Permission and Features, you are required to answer and provide screenshot of your app.
Take Video Screenshots to proceed.
Submit and provide further information.
App Icon: Upload an app icon (1024 x 1024) for the app display
App Purpose: Select "Yourself or your own business"
App Category: Choose the category for your app
After submittion for review, your "Start Verification" button should be activated.
You can start the Business Verifications again.