diff --git a/application/config/message.php b/application/config/message.php
index 4987ed519..af5861c55 100644
--- a/application/config/message.php
+++ b/application/config/message.php
@@ -4,6 +4,7 @@ if (! defined('BASEPATH')) exit('No direct script access allowed');
 
 $config['msg_delivery'] = true;
 $config['send_immediately'] = false; // If the message should be sent immediately
+$config['system_person_id'] = 1; // Dummy sender, used for sending messages from the system
 
 define('EMAIL_KONTAKT_TYPE', 'email'); // Email kontakt type
 define('SENT_INFO_NEWLINE', '\n'); // tbl_msg_recipient->sentInfo separator
diff --git a/application/controllers/api/v1/system/Message.php b/application/controllers/api/v1/system/Message.php
index 9e8af424e..585b7ba2b 100644
--- a/application/controllers/api/v1/system/Message.php
+++ b/application/controllers/api/v1/system/Message.php
@@ -132,7 +132,7 @@ class Message extends APIv1_Controller
 		if (is_object($validation) && $validation->error == EXIT_SUCCESS)
 		{
 			$result = $this->messagelib->sendMessage(
-				$this->post()['person_id'],
+				isset($this->post()['person_id']) ? $this->post()['person_id'] : null,
 				isset($this->post()['receiver_id']) ? $this->post()['receiver_id'] : null,
 				$this->post()['subject'],
 				$this->post()['body'],
@@ -204,10 +204,6 @@ class Message extends APIv1_Controller
 		{
 			return $this->_error('Parameter is null');
 		}
-		if (!isset($message['person_id']))
-		{
-			return $this->_error('person_id is not set');
-		}
 		if (!isset($message['subject']))
 		{
 			return $this->_error('subject is not set');
diff --git a/application/libraries/MessageLib.php b/application/libraries/MessageLib.php
index 7e89f2a7f..2739e1953 100644
--- a/application/libraries/MessageLib.php
+++ b/application/libraries/MessageLib.php
@@ -199,7 +199,9 @@ class MessageLib
     public function sendMessage($sender_id, $receiver_id, $subject, $body, $priority = PRIORITY_NORMAL, $relationmessage_id = null, $oe_kurzbz = null)
     {
         if (!is_numeric($sender_id))
-        	return $this->_error('', MSG_ERR_INVALID_SENDER_ID);
+        {
+			$sender_id = $this->ci->config->item('system_person_id');
+        }
 		
 		$receivers = null;