diff --git a/webapp/src/fixtures/utmCookie.tsx b/webapp/src/fixtures/utmCookie.tsx
index ad16216f91..9b02d3e31f 100644
--- a/webapp/src/fixtures/utmCookie.tsx
+++ b/webapp/src/fixtures/utmCookie.tsx
@@ -10,7 +10,7 @@ export function getUtmParams() {
     return {};
   }
   try {
-    return JSON.parse(atob(cookie));
+    return JSON.parse(atob(decodeURIComponent(cookie)));
   } catch (e) {
     Sentry.captureException(e);
   }