diff --git a/htdocs/comm/action/class/actioncomm.class.php b/htdocs/comm/action/class/actioncomm.class.php
index aa7d532025e..7c53a885043 100644
--- a/htdocs/comm/action/class/actioncomm.class.php
+++ b/htdocs/comm/action/class/actioncomm.class.php
@@ -196,6 +196,7 @@ class ActionComm extends CommonObject
         // Check parameters
         if (empty($this->userownerid))
         {
+            dol_syslog("You tried to create an event but mandatory property ownerid was not defined", LOG_WARNING);
         	$this->errors[]='ErrorPropertyUserowneridNotDefined';
         	return -1;
         }