diff --git a/src/app/Utils.php b/src/app/Utils.php
--- a/src/app/Utils.php
+++ b/src/app/Utils.php
@@ -91,9 +91,10 @@
      */
     public static function defaultView()
     {
-        // Return 404 for requests to the API end-points that do not exist
-        if (strpos(request()->path(), 'api/') === 0) {
-            return \App\Http\Controllers\Controller::errorResponse(404);
+        // Return standard empty 404 response for non-existing resources and API routes
+        // TODO: Is there a better way? we'd need access to the vue-router routes here.
+        if (preg_match('~^(api|themes|js|vendor)/~', request()->path())) {
+            return response('', 404);
         }
 
         $env = self::uiEnv();
diff --git a/src/tests/Unit/UtilsTest.php b/src/tests/Unit/UtilsTest.php
--- a/src/tests/Unit/UtilsTest.php
+++ b/src/tests/Unit/UtilsTest.php
@@ -48,6 +48,22 @@
         \App\IP6Net::where('net_number', inet_pton('2001:db8::ff00:42:0'))->delete();
     }
 
+    /**
+     * Test for Utils::defaultView()
+     */
+    public function testDefaultView(): void
+    {
+        // Non existing resources or api routes
+        $this->get('js/test.js')->assertNotFound()->assertContent('');
+        $this->get('vendor/test.js')->assertNotFound()->assertContent('');
+        $this->get('themes/unknown/app.css')->assertNotFound()->assertContent('');
+        $this->get('api/unknown')->assertNotFound()->assertContent('');
+
+        // Expect a view
+        $this->get('dashboard')->assertOk()->assertViewIs('root')->assertViewHas('env');
+        $this->get('unknown')->assertOk()->assertViewIs('root')->assertViewHas('env');
+    }
+
     /**
      * Test for Utils::emailToLower()
      */