NOTE: This works. We have just tested it.
Hi Just went through this. Facebook support was very unhelpful honestly. This is the workaround that worked for me
- Make sure you have completed your business information on the settings -> About section of the business manager page
- Turn on 2-factor authorisation for your admin users
- If the option still doesn’t appear – go to the facebook developer page and create an app – https://developers.facebook.com/apps/
- Associate the new app with your Facebook Business Page
- In your App dashboard – go to settings and basic and scroll down to business verificatio
- Click on verify here – for some absurd reason it works! – you will need to upload tax documents etc to verify
Hope this helps
Facebook verify my business button grayed out – how to Enable?
Source: https://developers.facebook.com/community/threads/1010572709333176/