diff --git a/Classes/Domain/Model/Mail.php b/Classes/Domain/Model/Mail.php
index 4438d2f59f471cb0ae2d001cfb84f9d6d5ac5154..428167d9b2ce29af354c416242056f3e6979a358 100644
--- a/Classes/Domain/Model/Mail.php
+++ b/Classes/Domain/Model/Mail.php
@@ -299,7 +299,7 @@ class Mail extends AbstractEntity {
 	 * @param int $sendingTime
 	 */
 	public function setSendingTime($sendingTime) {
-		$this->sendingTime = $sendingTime;
+		$this->sendingTime = (int) $sendingTime;
 	}
 
 	/**