diff --git a/src/Entity/Blog/Comment.php b/src/Entity/Blog/Comment.php
index edcbace..927bbe0 100644
--- a/src/Entity/Blog/Comment.php
+++ b/src/Entity/Blog/Comment.php
@@ -205,7 +205,7 @@ class Comment implements EntityInterface
      */
     public function getAvatar(): string
     {
-        return 'https://secure.gravatar.com/avatar/'.md5($this->getEmail()).'.jpg?s=90&d=retro';
+        return 'https://secure.gravatar.com/avatar/'.md5($this->getEmail() ?? 'undefined@undefined').'.jpg?s=90&d=retro';
     }
 
     /**