Step 1: Landing page
Confirm UTMs appear in the URL when you click the ad. If they are missing, attribution will fail downstream.
Step 2: Analytics
Confirm sessions show the correct source/medium/campaign.
Step 3: Conversion
Confirm conversions keep campaign association (where applicable). If you lose association, the conversion might happen on a different domain or after a redirect that strips parameters.
Tip
Expect platform differences, but huge gaps typically mean missing UTMs, consent blocking, or cross-domain issues.