Why did my conversion tracking stop after a website update? Tracking depends on specific pages, tags and form behaviour staying where they were. A redesign, a new thank-you page, a plugin update or a rebuilt form moves one of them, and the tracking stops without any error. The ads keep running. The account just stops seeing results, and starts making decisions without them.
What conversion tracking is, and the ways it gets built wrong in the first place, is a separate piece: what conversion tracking is and why most accounts get it wrong. This one is about tracking that worked and then stopped when the site changed.
What a site change actually breaks
Each of these is something I have had to find and fix on a real site, except the last, which I say so about.
The tag did not come with the rebuilt page. Tags usually live in the site's template, in the header. A new theme, a page rebuilt in a different builder, or a landing page moved to another tool starts from a clean template, and the tag is not in it. Everything else looks the same.
The form no longer loads a confirmation page. A lot of tracking is defined as "the thank-you page loaded". Then the form gets rebuilt to show a success message in place. The enquiries still reach your inbox, but the thank-you page nobody visits any more records zero. The opposite happens too: a form with no confirmation page at all, where the only thing to count is the click on the submit button, which counts people who pressed it and never finished.
A script on the page rewrote the form. Code added for one form, say to change where it submits depending on a choice, is written without limiting itself to that form. It rewrites every form on the page, including the newsletter box in the footer. Anything keyed to the original form behaviour stops matching.
The tag manager was swapped, or a second one added. Sites pile these up. I once opened a site's header and found three tag managers: the live one, an older one from a previous setup, and an orphan still loading an analytics tag Google retired years ago and an ad account nobody could identify. A migration that keeps the wrong one, or leaves two competing, produces numbers that are wrong in ways that look believable.
Two analytics IDs, one of them a decoy. Same shape. A site ends up with two analytics IDs, one connected to the ad account and one not. A redesign that keeps the wrong one reports traffic nicely and enquiries never.
The save did not save. The change was made in the site's admin, the page reloaded looking normal, and nothing was written. Twice I have watched a tracking edit look saved and be missing from the live page, with no error anywhere. If you are not checking the live page after a change, you do not know what shipped.
Consent or script blocking changed. A new cookie banner, a privacy plugin, a browser update. Tags that fired for everyone may now fire only for people who click accept, or for nobody, depending on how they were set up. This one I would expect rather than one from my own case notes, so treat it as a place to look, not a finding.
Why nobody notices
There is no error message. A tag that does not load does not report that it did not load. The ad platform sees fewer conversions and treats that as reality.
The numbers often drift rather than drop to zero. A form that goes to the thank-you page some of the time produces a line that looks like a slow month, and even a flat zero is easy to read as "the ads stopped working" instead of "the measurement stopped working".
And the person who changed the site is usually not the person watching the ad account. The web developer, the plugin or the owner editing a page had no reason to know a tag was there. The person running the ads sees the results change weeks later and starts adjusting bids, which is the expensive part: an account steering by numbers that are no longer connected to anything.
How to tell it happened to you
Take the two or three weeks before the site change and the two or three weeks after. For each, count the enquiries you actually got, from your inbox, booking system or phone log. Then look at what the ad account counted as conversions over the same weeks.
If the two moved together, the tracking survived. If the account's count fell and yours did not, the tracking broke. If the account's count jumped and yours did not, something is now counting things that are not enquiries, like the submit-button click above. You need your own records for this. Tracking cannot be checked against itself.
What to check after any site change
In this order, because each step is cheaper than the next.
- Load the live page in a real browser and watch what it requests. Not the page source, not a screenshot of the admin. Open the browser's network panel and look for the analytics request, the tag manager and the ad platform's conversion tag.
- Wait for the page to finish. Forms and buttons often appear a moment after the page does. Check too early and you find nothing. I once measured a button that existed twice on a page, one copy hidden, and checked the hidden one.
- Send a test enquiry from a private window. Then check whether the conversion shows up in the ad platform within a day or so. One real test beats any amount of inspection.
- Compare what the form does now with what the conversion is defined as. If the conversion is "thank-you page loaded", make sure the form still goes there. If it now confirms in place, the conversion needs redefining.
- Count the tag managers and analytics IDs. One of each is the normal picture. More than one is a question to answer, not always a problem.
- Check the admin again after a hard reload. If your edit is not there, it was never saved.
The version that checks every day
Everything above is for when you already suspect a problem. The other option is a scheduled check that reads the ad account every day and flags when enquiries stop arriving or start arriving at zero value. That is a monitoring job rather than a tracking job, and it has its own page: website monitoring.
For the tracking itself, building it so a site change is less likely to break it is part of how I run paid advertising. Where the site allows it, the conversion is counted when the site's server accepts the enquiry, rather than when a page loads or a button is pressed, so a redesigned thank-you page changes nothing the tracking relies on. Whether that means server-side tracking, and whether you need it, is covered in what server-side tracking is and when you need it.
All writing · Related: Your Google Ads stopped running. Nobody told you.