There might be only a few reasons why an ad account may be missing from the list.
Your Meta profile doesn't have the necessary permissions - make sure you are an admin of your Business Manager and the ad account you're trying to integrate;
It's just a delay after you added this ad account to your BM or got the admin permissions;
Meta's glitch which can be fixed by reconnecting Meta profile in integrations, adding and removing the ad account from your Business Manager, or toggling off and on the admin permissions for the ad account in Business settings:
1. Try reconnecting your Meta profile using one of the links below:Business profile: Re-authenticate →
Personal profile: Re-authenticate →
2. Remove the ad account from the Business Manager and add it back, try reconnection again, or
3. Toggle off and on the admin permissions for the ad account in Business settings:
If you have hundreds (or thousands) of ad accounts, you may not see the full list under Meta Ad accounts. In this case, please use the search function and enter the name of the ad account to find and connect it:
If the ad account is still hidden, you can try connecting a different profile - either a personal profile or a business profile. Just make sure that the profile has full admin rights to the ad account and Business manager.
Don't hesitate to contact our team if there are any questions.