Sorry for asking the obvious, but are you sure you are using a "Facebook custom audience" service?
And are you sure that your facebook account has access to the ad manager account you want to push custom audience data to?
finally, and tat might be the issue:
This means that is the smart list was empty when you created the audience and the leads qualified for the smart list later, they will not appear in the audience.
Thanks for your response.
Yes, Facebook custom audience service installed in Marketo instance (snapshot attached)
Yes, Facebook account has access to an Ad account we want custom audience to be created. I am able to see all other FB custom audience list exist in facebook account
No the smart list with leads created first and then tried to push those leads as a 'New audience' inside facebook using Ad bridge icon in the bottom of leads view of smart list.
We have the exact same issue using Ad bridge through to a Custom Audience. How did you get on here? Did you get a resolution?
I do not see any other reason why this would not work. Have you called in Support ?
How many leads are you pushing to Facebook? Perhaps it just didn't make any matches?
Primarily it is looking up to match on email addresses, so if you're a B2B company you might find this functionality limited for Facebook.
You could try switching the matching function to 'Advanced matching' to see if you can pick up more.
Lastly, you might want to check if Facebook has any restrictions in your jurisdiction on the size of the custom audience. If it is a small number I imagine FB wouldn't bother with a list because people within might be individually identifiable.