Cookie Consent Tools Blocking Test Cookies (Visits Log, Conversions Don’t)

If your site runs a cookie consent tool (CookieScript, Cookiebot, CookieYes, Complianz, Borlabs, Axeptio and similar), it can delete or block the cookies AB Split Test uses. The classic symptom: visits log fine, but conversions never do – the visitor reaches your thank-you page and the plugin can no longer tell which variation they saw.

How to check

Open your browser DevTools → Application → Cookies. Accept your own cookie banner, load the page running the test, then navigate to a second page. If the btab_... cookies disappear between page loads, your consent tool is cleaning them.

The fix: allow the plugin’s cookies

Add these cookie names to your consent tool’s allow list – typically the “Strictly necessary” or “Functional” category:

• btab_* – the test assignment cookie: which variation the visitor saw and whether they converted (e.g. btab_13956 for test 13956)
• abst_* – consent state and event queue helpers (abst_consent, abst_server_events)
• ab-advanced-id – repeat-visitor ID, only used when Advanced Tracking is enabled

These are first-party cookies set on your own domain. No third parties, nothing shared – they only exist so the same visitor sees a consistent variation and conversions can be attributed.

Tool-specific notes

CookieScript: in the dashboard, open your domain’s cookie list and add the names above to the category that runs without consent. Until they’re whitelisted, CookieScript wipes them on every page load.

Cookiebot, CookieYes, Complianz: AB Split Test detects these three automatically and can queue events until consent is given. The cookies still need to be allowed once the visitor accepts, so add them to the statistics/functional category as well.

Verify

Accept cookies in your banner → load the page with the test → continue to your conversion page → open Split Tests → your test → Logs. The visit and conversion should both appear within a minute or two.

Related: Choose When Test Visits Are Logged