Question from Reddit user:
Hi guys,
I am currently using Enhanced Conversion for Leads (similar to GCLID) as my offline conversions. I am seeing a difference in reported conversions to actual sales, and 90% of our traffic comes from PPC. I’m also seeing a lot of “The click for this conversion can’t be found” errors on my uploads.
My question is, if users initially use mobile, but convert on a difference device, how does google attribute that conversion when I import it?
Answer from Nabil:
The short answer is:
When you use Enhanced Conversions for Leads, Google attributes the cross-device conversion by using the hashed personal data you provide (usually an email address) to probabilistically link the offline conversion event to the user’s initial click on a mobile device, provided that user was signed into their Google account at the time of the click and the conversion.
The difference between reported and actual sales, and the “click for this conversion can’t be found” errors, are likely due to the Enhanced Conversions matching process failing because of data latency, minor data discrepancies, or the original click not having the necessary logged-in Google user signal.
A highly effective and reliable solution is to leverage the Google Ads API to upload conversions combined with a robust data collection method like server-side tagging to ensure maximum match quality.
The long answer is:
Your question goes right to the heart of modern, privacy-safe attribution.
Google Ads tracks cross-device offline conversions using a method based on Hashed User Data and Google’s internal network of signed-in users.
When you implement Enhanced Conversions for Leads, your website captures user-provided information, typically an email address, and hashes it using the SHA256 algorithm before sending it to Google.
Google then uses this hashed identifier to look for a match in its own system.
If the same user was signed into their Google account when they clicked your ad on their mobile device and later converts on their desktop device or offline, Google can probabilistically link the two events because both are associated with the same hashed user ID in Google’s ecosystem.
This is how the cross-device attribution works without relying on the physical Google Click ID (gclid) parameter.
Your reported issues – the difference between reported conversions and actual sales, and the high rate of “click for this conversion can’t be found” errors—indicate that your current client-side Enhanced Conversions implementation is likely suffering from data quality issues.
Common problems include a delay between when the user data is collected and when the Enhanced Conversions tag fires, inconsistencies in how data fields are collected, or simply the fact that the original click was not made by a user who was signed into Google.
To maximize your match rate and ensure reliability, an excellent solution is to use the Google Ads API for the offline conversion upload, but you first need to stabilize your data collection.
You should use a server-side tracking solution, like Stape or a Google Cloud Platform implementation, managed via Google Tag Manager.
Instead of sending the hashed data directly from the user’s browser, GTM sends the raw, first-party user data (like email and phone number) to your server container.
The server then performs the hashing and sends the clean, consistent data to Google.
When you upload your offline conversions, you bypass the client-side issues entirely and use the Google Ads API to send the highest-quality, most consistent user data, dramatically improving the match rate and ensuring that Google can correctly attribute those cross-device conversions.
This server-side approach reduces data latency, standardizes your hashing process, and ensures that the maximum number of your leads are attributed back to the correct mobile or desktop touchpoint.
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