diff --git a/application/Espo/Core/Record/Service.php b/application/Espo/Core/Record/Service.php
index faa0342a3f..023a72d57e 100644
--- a/application/Espo/Core/Record/Service.php
+++ b/application/Espo/Core/Record/Service.php
@@ -1270,7 +1270,7 @@ class Service implements Crud,
                         'couldNotAddFollowerUserHasNoAccessToStream',
                         'Stream',
                         [
-                            'userName' => $user->getUserName(),
+                            'userName' => $user->getUserName() ?? '',
                         ]
                     )
                     ->encode()