Your Client's Developer Broke Conversion Tracking and Nobody Told You

You log into Google Ads on Monday morning. The client's campaign that was converting at 4% last week is now showing zero conversions over the last three days. Clicks are steady. Impressions are steady. Cost-per-click hasn't moved. But conversions? Flatlined. You start questioning everything you've built. Then you find out their developer pushed a site update on Thursday. Nobody told you.

This Happens All the Time. More Than You Think.

If you manage Google Ads for clients, this scenario isn't hypothetical. It happens constantly. Here's the chain of events:

1. The client decides to redesign their website, add a new form plugin, migrate to a new CMS, or "just update a few pages."
2. Their developer (in-house, freelance, cousin who knows WordPress) makes the changes and pushes them live.
3. The Google Ads conversion tag, the Google Tag Manager container, or the thank-you page redirect gets overwritten, removed, or broken in the process.
4. Nobody tells the agency. Nobody even thinks to. The developer doesn't know conversion tracking exists. The client doesn't know it's tied to specific code on specific pages.
5. Three to seven days go by before you notice. By then, the client is emailing you asking why the ads "stopped working."

The ads didn't stop working. The measurement broke. But your client doesn't know the difference, and that distinction is now your problem to explain.

From our diagnosis work:Roughly 1 in 4 "my Google Ads stopped converting" cases we investigate turn out to be broken conversion tracking — not campaign problems. The conversion tag stopped firing, and the campaigns were blamed for something that had nothing to do with them.

The Symptoms: What Broken Conversion Tracking Looks Like

Broken tracking has a very specific fingerprint. Once you know what to look for, you can spot it in about 60 seconds inside the Google Ads interface.

The telltale signs:

• Sudden drop to zero or near-zero conversions. Not a gradual decline — a cliff. The campaign was converting Tuesday, and Wednesday it stopped. Gradual declines are usually performance issues. Cliffs are almost always tracking issues.
• Clicks and impressions remain stable. If clicks also dropped, you might have a budget problem, a bidding change, or a competition shift. When clicks are steady but conversions disappear, the ads are still doing their job — the measurement layer is broken.
• All campaigns are affected simultaneously. If one campaign drops, it could be a campaign-level issue. If every campaign in the account drops at the same time, it's almost certainly a tracking problem or a site-wide issue.
• The conversion status in Google Ads changes. Go to Goals > Conversions > Summary. If the status column says "No recent conversions" or "Inactive" instead of "Recording conversions," that's your answer.
• GA4 shows a similar drop — or doesn't. If GA4 also shows zero form submissions, the forms themselves might be broken. If GA4 still shows traffic and events but Google Ads shows no conversions, the Google Ads conversion tag specifically is the issue.

How to Verify: Step-by-Step Diagnosis

Once you suspect the conversion tracking is broken, here's the exact process to confirm it and find out what happened.

1. Check Google Tag Assistant (the Chrome extension)

Install the Google Tag Assistant Legacy extension or use the Tag Assistant at tagassistant.google.com. Navigate to the client's landing page, then navigate through the conversion flow — fill out the form, submit it, and land on the thank-you page.

• Look for the Google Ads conversion tag (AW-XXXXXXXXX). Is it present on the thank-you page? If it's missing entirely, the tag was removed.
• If the tag is present, does it fire? Tag Assistant will show you if the tag triggered successfully or if it errored out.
• Check if the conversion linker tag is present. Without the conversion linker, the Google Ads tag can't attribute conversions correctly, even if it fires.

2. Check Google Tag Manager

If the client uses GTM, log into Tag Manager and check:

• Is the GTM container still installed on the site? View the page source (Ctrl+U or Cmd+Option+U) and search for "GTM-". If the GTM container code is gone, the developer removed it during the update. Every tag inside GTM — conversion tracking, remarketing, analytics — is gone with it.
• Use GTM Preview mode. Click Preview in the GTM workspace, enter the client's URL, and walk through the conversion flow. You can see exactly which tags fire on which pages and which triggers are working.
• Check the trigger. If the conversion tag fires on a thank-you page URL (e.g., /thank-you), and the developer changed that URL to /confirmation or /success, the trigger no longer matches. The tag exists but never fires.
• Check the GTM version history. Did someone publish a new GTM version recently? Sometimes the client's developer goes into GTM to "clean things up" and deletes tags they don't recognize.

3. Inspect the Thank-You Page Source Code

If the client isn't using GTM and has the conversion tag hardcoded, go to the thank-you page directly and view the source code.

• Search the source for "AW-" or "conversion" or "gtag". If nothing comes up, the code was stripped out during the site update.
• Check if the thank-you page even exists anymore. If the developer rebuilt the forms, the old thank-you page might be gone or redirecting somewhere else.
• Check for JavaScript errors in the browser console (F12 > Console). Sometimes the gtag code is present but a JS error on the page prevents it from executing.

4. Cross-Reference with GA4

Open GA4 and check the same date range.

• If GA4 also shows zero events/conversions: The problem is likely site-wide. Either GTM was removed, or the forms themselves are broken, or the entire tracking setup was wiped.
• If GA4 shows normal traffic and events but Google Ads shows no conversions: The Google Ads conversion tag specifically is broken. GA4 tracking survived the update, but the Google Ads tag didn't.
• Check the Realtime report in GA4. Submit a test form right now. If the event shows up in GA4 Realtime but the Google Ads tag doesn't fire in Tag Assistant, you've isolated the problem precisely.

5. Pinpoint the Exact Date It Broke

In Google Ads, set the date range to the last 30 days and segment by day. Find the exact date conversions dropped to zero. Then ask the client: "Were any changes made to your website around [that date]?" Nine times out of ten, the dates match.

You can also check the Wayback Machine (web.archive.org) to see if recent snapshots of the site are different. Or ask the client for access to their hosting change log, CMS revision history, or deployment logs.

The Conversation with the Client

This is the part most agencies fumble. You've diagnosed the problem. Now you need to explain it to the client without sounding defensive, without blaming their developer personally, and without losing credibility.

Here's the framework we recommend:

"We investigated the conversion drop and found that your website was updated on [specific date]. During that update, the conversion tracking code was removed from the [thank-you page / entire site / form]. Conversion tracking stopped recording on [specific date], which matches exactly. The ad campaigns themselves continued running normally — clicks, impressions, and ad performance were unaffected. This is a website issue, not a campaign issue. Here's what we need your developer to reinstall, and we'll verify it's working once it's back in place."

Key principles for this conversation:

• Lead with dates and data. "Your site was updated March 12. Conversions stopped March 12." Matching dates are impossible to argue with.
• Separate the campaigns from the tracking. Make it very clear: the campaigns were doing their job. The problem was that the measurement system was removed. These are two different systems.
• Don't blame the developer by name. Say "the tracking code was removed during the website update" — passive voice, factual. Don't say "your developer broke it." Even if that's exactly what happened.
• Offer the fix, not just the diagnosis. Give them the exact code snippet or GTM instructions their developer needs to reinstall. Be the solution, not just the messenger.
• Explain what was lost. "During the [X] days the tracking was down, we were still generating clicks and likely generating leads, but we have no conversion data for that period. That data is gone — we can't recover it retroactively."

Prevention: How to Stop This from Happening Again

You can't control when a client updates their website. But you can build systems that catch the breakage fast — ideally before the client even notices.

Set Up Google Ads Conversion Alerts

• In Google Ads, go to Tools > Rules > Create Rule. Set a custom rule that emails you if conversions drop below 1 for any 48-hour period while spend is above $0. This catches most tracking failures within two days.
• Set up a Google Ads script that checks conversion counts daily and sends a Slack or email alert if conversions are zero for two consecutive days. There are free templates for this — search "Google Ads script zero conversions alert."

Run Monthly Tracking Audits

• Once a month, walk through the conversion flow on every client's website. Fill out the form. Submit it. Check Tag Assistant. Verify the tag fires. This takes 5 minutes per client and catches problems before they cost you a week of data.
• Check the conversion status column in Google Ads monthly. Make sure every conversion action still says "Recording conversions."
• Compare Google Ads conversion counts against GA4 event counts for the same period. If they diverge significantly, something changed.

Document the Tracking Setup

• Create a tracking documentation sheet for every client. Include: conversion action names, conversion IDs, which pages the tags are on, whether tracking is via GTM or hardcoded, what the thank-you page URL is, and who has access to GTM.
• Share this document with the client and tell them explicitly: "If your website is updated, your developer needs to keep these tags in place. Here's what they are and where they go."
• Include a line in your client contract or onboarding document: "Client agrees to notify [Agency] before any website changes that affect tracked pages, including redesigns, CMS migrations, form plugin changes, and URL structure changes."

Use Google Tag Manager (If They're Not Already)

If the client has hardcoded tracking tags on their site, push to move everything into GTM. When tracking lives inside GTM, a website redesign is less likely to break it — the developer only needs to keep the single GTM container snippet in the header. All the conversion tags, triggers, and variables live inside GTM, which is separate from the website code.

It's not bulletproof — developers can still remove the GTM container — but it reduces the surface area. One snippet to maintain instead of five or six separate tags across multiple pages.

The Post-Website-Change Checklist

Send this to your clients. Better yet, make it part of your onboarding. Any time the client tells you their site was updated — or you discover it was — run through every item.

1. Verify the GTM container (or global site tag) is still in the page source. View source on the homepage and at least one landing page. Search for "GTM-" or "gtag."
2. Walk through the full conversion flow. Click an ad (or visit the landing page), fill out the form, submit it. Land on the thank-you page. Do this on both desktop and mobile.
3. Check Tag Assistant during the conversion flow. Confirm the Google Ads conversion tag fires on the thank-you page. Confirm the conversion linker is present on all pages.
4. Verify the thank-you page URL hasn't changed. If the old URL was /thank-you and it's now /contact/success, your GTM trigger is broken.
5. Check Google Ads conversion status. Go to Goals > Conversions > Summary. Confirm the status is "Recording conversions."
6. Cross-reference a test submission in GA4 Realtime. Submit the form and check if the event appears in GA4 within 30 seconds.
7. Verify phone call tracking (if applicable). Is the dynamic number insertion script still on the site? Call the number from a mobile device and check if it records in your call tracking platform.
8. Check all landing page URLs in your campaigns. If the site migration changed URL structures (e.g., /services/plumbing became /plumbing-services), your ads are now pointing to 404 pages. Check every active ad URL.
9. Check remarketing/audience tags. If you're running remarketing campaigns, verify those tags are still firing too. They often break alongside conversion tags.
10. Document what changed and when. Note the date of the website update, what broke, what was fixed, and who fixed it. Keep this in the client's file. You'll need it next time.

The Real Cost of Broken Tracking

Broken conversion tracking doesn't just mean missing data. It causes a cascade of problems that compound the longer it goes undetected:

• Smart Bidding goes blind. If you're using Target CPA, Maximize Conversions, or Target ROAS, the algorithm relies on conversion data to make bidding decisions. With zero conversions feeding back, the algorithm either panics and overbids to "find" conversions, or it pulls back and reduces traffic. Either way, you're burning money or losing volume while the system recalibrates.
• You lose optimization data permanently. Conversions that happened during the tracking blackout are gone. You can't backfill them. That's days or weeks of learning data that Smart Bidding will never get back.
• The client loses trust in your work. Even after you explain the tracking issue, the client remembers "the ads stopped working for two weeks." That seed of doubt is hard to undo.
• You can't report accurately. Your monthly report now has a hole in it. Your cost-per-lead numbers are inflated because the denominator (conversions) is wrong. You end up having to add asterisks and footnotes explaining a problem that wasn't yours.

A Note on Client Communication Going Forward

After this happens once — and it will — add a standing item to your client communication. In every monthly check-in or report, include a one-liner: "Conversion tracking status: Active and recording. Last verified: [date]." This does two things. It shows the client you're monitoring proactively. And it creates a paper trail showing that tracking was confirmed working on your end, so if it breaks after a website change, the timeline is clear.

You can't prevent clients from updating their websites without telling you. But you can make it a 48-hour problem instead of a 2-week problem. And when the conversation comes, you can walk in with dates, data, and a fix — not guesses and excuses.

We Check Tracking Health in Every Diagnosis

At Prove My Ads, conversion tracking verification is the first thing we check in every Campaign Diagnosis. Not because it's the most exciting part — but because it's the most common cause of "the ads aren't working" that we find.

We verify the full tracking chain: Google Ads tags, GTM configuration, GA4 cross-reference, thank-you page integrity, and conversion action status. If it's broken, we tell you exactly what's broken, when it broke, and what needs to be reinstalled. If it's working, we move on to diagnosing the actual campaign performance.

$497. Read-only access. 3–5 business days. You get a full report with findings your client can't argue with.