diff --git a/src/EventSubscriber/GoogleAnalyticsConfig/DefaultConfig.php b/src/EventSubscriber/GoogleAnalyticsConfig/DefaultConfig.php
--- a/src/EventSubscriber/GoogleAnalyticsConfig/DefaultConfig.php
+++ b/src/EventSubscriber/GoogleAnalyticsConfig/DefaultConfig.php	(date 1662585819382)
@@ -83,7 +83,7 @@
     // Per RFC 2109, cookie domains must contain at least one dot other than the
     // first. For hosts such as 'localhost' or IP Addresses we don't set a
     // cookie domain.
-    if ($domain_mode == 1 && count(explode('.', $cookie_domain)) > 2 && !is_numeric(str_replace('.', '', $cookie_domain))) {
+    if ($domain_mode == 1 && count(explode('.', $cookie_domain ?? '')) > 2 && !is_numeric(str_replace('.', '', $cookie_domain))) {
       $arguments = array_merge($arguments, ['cookie_domain' => $cookie_domain]);
       $javascript->setAdsenseScript($cookie_domain);
     }