diff --git a/app/Http/Controllers/MailController.php b/app/Http/Controllers/MailController.php
index ca50af6..471ed9f 100644
--- a/app/Http/Controllers/MailController.php
+++ b/app/Http/Controllers/MailController.php
@@ -80,14 +80,14 @@ function ($attribute, $value, $fail) {
 
         $max_received_at = Mail::where([
             ['to_hash', '=', $to_hash],
-            ['received_at', '>=', $key],
+            ['received_at', '>', $key],
         ])
         ->orderBy('received_at', 'desc')
-        ->value("received_at");
+        ->value("received_at") ?? $key;
 
         $new_email_list = Mail::where([
             ['to_hash', '=', $to_hash],
-            ['received_at', '>=', $key],
+            ['received_at', '>', $key],
         ])
             ->select([
                 'id as key',