diff --git a/src/app/Http/Controllers/API/V4/NGINXController.php b/src/app/Http/Controllers/API/V4/NGINXController.php
--- a/src/app/Http/Controllers/API/V4/NGINXController.php
+++ b/src/app/Http/Controllers/API/V4/NGINXController.php
@@ -125,6 +125,11 @@
         $username = $this->normalizeUsername($request->headers->get('Php-Auth-User', ""));
         $password = $request->headers->get('Php-Auth-Pw', null);
 
+        if (empty($username)) {
+            //Allow unauthenticated requests
+            return response("");
+        }
+
         if (empty($password)) {
             \Log::debug("Authentication attempt failed: Empty password provided.");
             return response("", 401);
diff --git a/src/tests/Feature/Controller/NGINXTest.php b/src/tests/Feature/Controller/NGINXTest.php
--- a/src/tests/Feature/Controller/NGINXTest.php
+++ b/src/tests/Feature/Controller/NGINXTest.php
@@ -210,7 +210,7 @@
         $john = $this->getTestUser('john@kolab.org');
 
         $response = $this->get("api/webhooks/nginx-httpauth");
-        $response->assertStatus(401);
+        $response->assertStatus(200);
 
         $pass = \App\Utils::generatePassphrase();
         $headers = [
@@ -248,7 +248,7 @@
         $modifiedHeaders = $headers;
         $modifiedHeaders['Php-Auth-User'] = "";
         $response = $this->withHeaders($modifiedHeaders)->get("api/webhooks/nginx-httpauth");
-        $response->assertStatus(403);
+        $response->assertStatus(200);
 
         // Invalid User
         $modifiedHeaders = $headers;