KB-1538 Receive message node throws error when importance flag is null


The following error is seen when capturing msg!properties'.'Importance and the Receive Message node fails:

Problem:  This notification is sent for canceled event messages of type Email.

Details:  Canceled consumed message in Message Expression Out (ERROR:EVAL:@reason=Invalid index: Cannot index into Deferred) for message sent to persistent id XXXX on named port 'Await Incoming Email'. The process itself has not been canceled and may continue to consume events.

Recommended Action:  Check the message listener for correctness. Cleanse the source of the message, if the message itself has caused the failure. For email events, place a spam filter in front of the event listener.

Priority of this problem: Normal Priority


This is because the importance flag was not set for the email on the senders side and the value is null, which is causing the node to error out.


In order to avoid the null value, use the property() function. This will allow users to set a default value to return, if the importance of the email is not set.

Affected Versions

This article applies to all versions of Appian.

Last Reviewed: March 2018