The short answer
- Legitimate loss: visitors who decline are no longer measured with cookies. That's the law, and clever technology doesn't change it.
- Technical loss: visitors who accept are still not measured, because their consent doesn't reach Google or Meta properly. That's often a large part of the apparent drop, and it can be fixed.
- Test it yourself: click "accept" in a private window and check whether your tags actually load afterwards. If they don't, your problem is technical, not your ads.
First, the rules: why working around consent is not an option
Across the EU and UK, tracking cookies may only be placed with freely given, informed consent. Regulators enforce this actively. The Dutch Data Protection Authority, for example, has been checking cookie banners structurally since April 2025. By November 2025 it had written to more than 200 websites about misleading banners; around three quarters changed their banner, and those who don't can expect an investigation or a fine (privacy-web.nl, 11 Nov 2025).
So the answer to disappearing conversions is never a banner that makes declining harder, or tracking that carries on after a "no". The answer is making sure every "yes" is actually passed on as a "yes".
How consent should reach your tags
Google: four consent signals
Google uses Consent Mode, where your banner passes on four signals (Google documentation):
- ad_storage: may advertising cookies be used?
- analytics_storage: may analytics cookies be used?
- ad_user_data: may user data be sent to Google for advertising?
- ad_personalization: may ads be personalised, for example remarketing?
There are two ways to set it up. In basic mode, Google tags only load after the visitor makes a choice, and nothing is sent when they decline. In advanced mode, tags load straight away with consent set to "denied" by default, and cookieless measurements are still sent when someone declines, which Google uses to model missing conversions. Which mode fits your situation is a deliberate choice; if you're unsure about the legal side, a privacy lawyer is the right person to ask.
Meta: the pixel needs to know there's consent
The Meta pixel has its own consent function. consent revoke pauses sending pixel events, and consent grant resumes them after the visitor gives consent. Meta notes you need to call the pause on every page (Meta documentation).
The technical errors we see most often
- The banner remembers the choice, but tells no one. The visitor clicks accept, the banner disappears, but no "consent granted" signal goes to Google or Meta. Result: nobody is measured, not even those who said yes.
- The order is wrong. Tags load before the default setting is in place, or the "yes" arrives after the page has already been measured. Then you miss the first and most important page view.
- "Yes" only works on the first page. On the next page, or in the checkout, the pixel is paused again. Exactly where the purchase happens.
- The checkout or thank-you page sits outside the banner. An external checkout or payment page doesn't know the visitor's choice, so the purchase event isn't sent, or is sent incorrectly.
- Server-side tracking ignores the choice. Events sent from your server are covered by consent too. Server-side tracking is a way to measure more accurately, not a way around a "no".
Check it in ten minutes
- Open your site in a private window and click decline. No requests with cookies should go to Google Analytics or Meta.
- Open a new private window and click accept. Click through to a product page and the checkout. Now your tags should load, on every page.
- Check Meta's Events Manager (test events) and Google's Tag Assistant to see whether events and the consent signal come in.
- Compare measured purchases per day with your real orders, before and after the banner. A reasonable gap is normal (those are the people who declined); a much bigger gap points to a technical error.
How we do it ourselves
On sasdamx.com, Google Analytics only loads after a visitor clicks "accept", and anyone who declines isn't tracked with cookies. For overall visits we also use an analytics tool that works without cookies. That keeps measurement honest and still useful, and we know how many people visit the site.
Why this matters
If you don't know which part of the drop is legitimate and which part is an error, you make the wrong decisions: switching off ads that work fine, or "fixing" tracking in a way that breaks the law. Get the technology right first, then draw conclusions about your campaigns. That's exactly where creative and measurement meet.