Since the last Facebook iOS 14 updates, a verified domain needs to be provided for Facebook Conversion campaign objective. We've integrated this specificity in our campaign creation flow.
You'll indeed find a dropdown "Conversion domain" field in which you can simply enter your verified domain or select it from the list if you already used it before:
How to set my Verified Domain?
The setting of Verified Domains must be done on your Facebook Business Manager, you'll find all the info on how to do it in the video demo available on Facebook documentation here and more details here.
In brief, you need to go in Business settings > Brand Safety > Domains to add your verified domains and link them to the right Facebook page(s) through the "Add Assets" button:
How do I set Aggregated Event measures?
Aggregated Event measures need to be set on Business Manager in Events Manager. You can set up to 8 measures per verified domain. Once in Data Source in your Events Manager, you can click on Manage Events under Aggregated Event Measurement:
You'll then see all you verified domains listed and the number of events configured for each.
Click on a verified domain to see the details of your configured events and go on Manage Events to set more:
The aggregated Event measures must be linked to the right Facebook pixel or ad account so that they are available to use in Paragone. You'll find Facebook guidelines on this topic here.