diff --git a/lib/Util/Polyfills.php b/lib/Util/Polyfills.php
index 4f45f31dd3..e15caa4a94 100644
--- a/lib/Util/Polyfills.php
+++ b/lib/Util/Polyfills.php
@@ -1,6 +1,6 @@
 <?php
 
-use Symfony\Polyfill\Mbstring\Mbstring as MbstringPolyfill;
+use MailPoetVendor\Symfony\Polyfill\Mbstring\Mbstring as MbstringPolyfill;
 
 if (!function_exists('mb_detect_encoding')) {
   function mb_detect_encoding($str, $encodingList = null, $strict = false) {