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Severity: HighOwner: DevTime to fix: 30-90 min

Consent banner not showing on mobile

Fix viewport, CSS, and lazy-load issues that make the consent banner disappear or fail to render on mobile devices.

Covers: mobile_banner_missing, consent_banner_mobile

Why this matters

A banner that works on desktop but fails on mobile still creates a compliance gap for a major share of traffic and can be easy to miss during desktop-only QA.

How to verify manually

  1. Open the site in mobile viewport emulation and on a real phone if possible.
  2. Check whether the banner renders above the fold and is not clipped or hidden.
  3. Inspect CSS, z-index, and lazy-loaded containers affecting the banner.

Typical root causes

  • Responsive CSS hides the banner container below a breakpoint.
  • The banner loads inside a component that does not render on mobile.
  • Sticky headers, overlays, or modals cover the banner.

GTM fix

  1. Review whether mobile-specific tag or CMP triggers differ from desktop.
  2. Ensure the CMP still initializes for mobile page variants.
  3. Retest on multiple breakpoints after publish.

WordPress fix

  1. Check mobile theme settings, cache plugins, and optimization plugins that alter script order.
  2. Ensure the CMP plugin outputs the banner on mobile templates too.
  3. Test with cache and optimization features disabled if behavior differs.

Generic fix

  1. Audit responsive CSS and viewport-specific rendering conditions.
  2. Make sure the banner renders early and above competing overlays.
  3. Treat mobile as a separate compliance path in QA, not as a desktop variant.

How to confirm the fix worked

  • Confirm the banner appears on a real mobile device.
  • Confirm users can Accept and Reject on mobile.
  • Run a fresh scan with mobile evidence if supported and confirm the issue clears.

Next step

Re-scan after deployment to confirm that the runtime behavior changed, not just the banner copy.

Consent banner not showing on mobile — GDPR Fix Guide