Why it happens
Low Event Match Quality. Meta scores how well the customer details on your purchases let it find the person who saw your ad. A low score usually means few purchases carry an e-mail, phone or click ID, often because they come from the browser only. Read low Event Match Quality for Purchase.
Purchase is missing value, currency or content IDs. Some Purchase events arrive without the order value, without a currency, or without product IDs. Usually one sender, such as old theme code or a second app, leaves the field out. Read missing value, currency or content IDs.
Low deduplication, or missing deduplication parameters. Meta gets the same purchase from the browser and from a server and cannot tell they are one, because the two copies do not share an event ID. Read Meta event deduplication on Shopify. If Meta's count is already higher than your orders, see Meta counts purchases twice.
Events from a new or unverified domain. Meta notices that your pixel sends events from a domain it has not seen, or asks you to verify your domain. Domain verification proves you own the domain, and it is rarely why purchases are missing. Read Meta domain verification on Shopify.
Server sending a modified fbclid in the fbc parameter. A server changed the Meta click ID before sending it, for example by lowercasing it. Read Meta says your server sends a modified fbclid.
No warning, but no events either. Not every problem shows up as a Diagnostics issue. If purchases from your server stop arriving, the Conversions API access token may have expired or been revoked. Read Meta Conversions API access token stopped working. If your server gets a positive reply from Meta but nothing appears in Events Manager, the events usually went to another dataset or carry an old time. Read Conversions API events received but not showing.
Check it yourself
- 1In Meta Events Manager, open Data sources and pick the dataset your ads use. Open the Diagnostics tab.
- 2Start with the Active tab. Meta lists an issue there when it was detected in the last 24 hours and you have not marked it resolved or ignored.
- 3Fix critical issues first. Meta marks them with a red icon and warnings with a yellow one. Each issue has a description and steps.
- 4Note which event each issue names. This page is about Purchase, the event your sales and ad results are measured by.
- 5Open the History tab to see what changed in your pixel and Conversions API around the day an issue appeared, and who changed it.
- 6After a fix, check the next day. Meta moves an issue it does not detect the following day to Previously detected. If Meta detects it again after 3 days, it moves back to Active.
FAQ
Can I ignore Diagnostics warnings?
You can click Ignore, and Meta moves the issue to the Ignored tab. Meta says that an issue you do not act on within 3 days moves to Previously detected, and its instructions are removed. Read each one before it goes.
Does a warning mean purchases are not counted?
Not on its own. Meta calls warnings low-priority issues, and most of the ones above are about the details a purchase carries. Compare Meta's Purchase count on the Overview tab with your paid online orders for the same days to see whether purchases are missing.
What makes an issue critical rather than a warning?
Meta says critical issues address high-priority changes to your event setup, due to things such as platform updates, changing privacy rules and violations of Meta's Privacy Policy, and should be fixed promptly. Warnings are low-priority issues. Meta's examples are a value parameter that may be set up wrong and a pixel that recently started sending events from new domains.
Who sees an issue I mark as resolved?
Meta says that for web events, Ignore and Mark as resolved apply to everyone in the business portfolio.
My count is far from my Shopify orders, but Diagnostics is empty. Where do I start?
Diagnostics only lists what Meta can detect. Start with Meta shows fewer purchases than Shopify.