diff --git a/src/Service/Router/RoutingBuilder.php b/src/Service/Router/RoutingBuilder.php
index 8d8700216..68e22a718 100644
--- a/src/Service/Router/RoutingBuilder.php
+++ b/src/Service/Router/RoutingBuilder.php
@@ -253,9 +253,7 @@ private function applyCustomDomain(string $url): string
         # then always use this one and override existing ones
         if ($customDomain !== '') {
             $components = parse_url($url);
-            $host = (is_array($components) && isset($components['host'])) ? (string)$components['host'] : '';
-            # replace old domain with new custom domain
-            $url = str_replace($host, $customDomain, $url);
+            $url = $customDomain . ($components['path'] ?? '');
         }
 
         return $url;
diff --git a/tests/PHPUnit/Service/Routing/RoutingBuilderTest.php b/tests/PHPUnit/Service/Routing/RoutingBuilderTest.php
index 4290ea003..323403537 100644
--- a/tests/PHPUnit/Service/Routing/RoutingBuilderTest.php
+++ b/tests/PHPUnit/Service/Routing/RoutingBuilderTest.php
@@ -57,7 +57,7 @@ public function testWebhookUrlWithCustomDomain(): void
         # prepare our fake server data
         # assign a current domain to replace.
         # also configure our environment variable
-        $builder = $this->createBuilder('https://local.mollie.shop/notify/123', '123.eu.ngrok.io');
+        $builder = $this->createBuilder('https://local.mollie.shop/notify/123', 'https://123.eu.ngrok.io');
 
         $url = $builder->buildWebhookURL('-');