1. The Conversion ID Check (The Credentials Mismatch)
The Shopify "Google & YouTube" app acts as a bridge. For the bridge to work, it needs the exact credentials for your Google Ads account and the specific action you want to track.
What to Look for:
The AW ID: You need to confirm the AW-XXXXXXX ID showing in your Google Ads account is the exact one connected in the Shopify app settings. If you have multiple Google Ads accounts (e.g., a manager account structure), it's easy to link the wrong one.
Manual ID/Label Entry: Sometimes, even when linked, the app requires you to manually confirm the Conversion Label for the Purchase event. If you created a custom conversion action in Google Ads before linking Shopify, the app may not automatically grab its specific label, resulting in the data being sent into a black hole.
How to Fix:
In Google Ads: Go to Tools & Settings → Conversions. Click on your main Purchase conversion action. In the Tag setup section, copy the Conversion ID (AW-XXXXXX) and the Conversion Label (the string of letters/numbers next to the ID).
In Shopify: Go to the Google & YouTube app settings. Find the section for Conversion Tracking and paste those exact ID and Label values where prompted to ensure perfect alignment.
2. Duplicate Tags (The Code Conflict)
This is a classic "too many cooks in the kitchen" problem. If you manually installed a Google Tag or a Google Tag Manager snippet into your Shopify theme or checkout scripts before using the app, that old code is likely intercepting or blocking the new app's signal.
What to Look for:
How to Fix:
Remove Manual Code: If you find any code snippets starting with gtag('config', 'AW-XXXXXX') or the full GTM container code that you pasted manually, delete it completely from the Shopify code files.
Rely Solely on the App: The official app is designed to manage all Google tracking seamlessly. If you let it handle the entire process, it removes the risk of conflicts on the front-end.
3. The Conversion Action Setup (The Google Ads Configuration Error)
The Shopify app sends raw purchase data to Google Ads, but Google Ads still needs to be told what to do with that data.
What to Look for:
Goal Status: In Google Ads, your Purchase conversion action is often mistakenly left as "Secondary" or, worse, "Removed." If it's secondary, Google Ads won't use that data for automated bidding strategies (like Maximize Conversions), and it may not even show up in the main reporting columns.
Source Misconfiguration: You must ensure the Purchase conversion action is configured to correctly receive data from the Shopify platform (the linked account source), not trying to track a page view or another manual source.
How to Fix:
Set to Primary: Go to Tools & Settings → Conversions. Find your key Purchase conversion action and ensure the Goal Optimization setting is set to "Primary action."
Check Reporting Delay: Once everything is fixed, conversions may still take up to 24 hours to appear. Don't panic if they don't show up immediately.
If you methodically check and correct these three points, your purchase data should begin flowing correctly from Shopify to Google Ads.