Why is Google not correctly recognizing the consent status of my visitors?

Google does not recognise your visitors’ consent status correctly when the default consent state is set too late, the consent update after the banner click never reaches the Google tags, or consent mode v2 parameters are missing. In all three cases the banner seems to work, but Google tags act on the wrong state, for example treating visitors who accepted as if they had declined.

Consent mode needs two steps on every page: a default state before any tag fires, and an update as soon as the visitor makes a choice. The update must happen on the page where the click occurs, before the visitor navigates. If either step is missing or comes in the wrong order, the consent status in Google products is wrong.

What are the usual causes?

• Default set too late. If a tag reads or writes cookies before the default is set, the default has no effect. Typical cause: the consent command sits below the Tag Manager snippet, or is set asynchronously.
• Custom HTML instead of a template. Google advises against calling the gtag consent command from a custom HTML tag in Tag Manager. Use a consent mode template from your consent management platform (CMP) that fires on the Consent Initialization trigger.
• Update missing or too late. The CMP stores the choice in its own cookie but never sends a consent update, or only sends it on the next page.
• Only two of four parameters. Setups from before consent mode v2 only send ad_storage and analytics_storage. Without ad_user_data and ad_personalization, Google treats ads measurement and personalisation as not consented.
• Regional settings. Defaults are scoped to the wrong regions, so visitors from some countries get no default or the wrong one.
• Asynchronous banner. If the CMP loads after the Google tags, they send data before the update. The wait_for_update setting gives the banner a short time to send its update.

How do I check what Google receives?

1. Open Tag Assistant and enter your website’s URL. If it cannot connect, your banner may be blocking the Tag Manager container until consent.
2. In the Summary, select the earliest Consent event. Under API Call, ad_storage, analytics_storage, ad_user_data and ad_personalization must all have a default value. Alternatively, check the column On-page Default in the Consent tab.
3. Click accept on the banner and select the most recent Consent event. All four parameters must now show the new values (column On-page Update).
4. Under Tags, check which tags fired and whether each one received the consent it requires.
5. If you use regional defaults, repeat the test with a simulated location from another region.
6. In the browser’s developer tools under Network, look at requests to Google. The gcs parameter carries the consent state; it should change after your click, for example from G100 to G111.

How do I fix it permanently?

• CMP with consent mode v2. Switch on Google consent mode in your CMP and use its Tag Manager template on Consent Initialization – All Pages.
• Correct order. With gtag.js, place the default command above all tag snippets. In Tag Manager, fire other tags only after consent initialization.
• Update on the same page. Make sure the CMP sends the update immediately after the click, not after a reload.
• Test after every change. Re-test accept, decline and returning visit in Tag Assistant after CMP or container updates.

Set the default for all four consent mode v2 parameters before any tag, send the update on the same page as the click, and verify both events in Tag Assistant. Most recognition problems disappear once that order is right.

If the banner prevents Tag Manager from loading at all, see our FAQ on why a consent banner blocks Google Tag Manager.

Sources

• Google for Developers: Troubleshoot consent mode with Tag Assistant
• Google for Developers: Set up consent mode on websites
• Tag Manager Help: Tag Manager consent mode support
• Analytics Help: Verify and update consent settings in Google Analytics

Not sure which consent state Google really receives from your website? We test your banner, Tag Manager and consent mode v2 step by step and fix the order. Book a free intro call or read more about our tracking agency.