Answer

PROBLEM

Microsoft Exchange server prompts the error '452 4.3.1 Insufficient system resources' message in the control panel.

ENVIRONMENT

• GFI FaxMaker
• GFI MailEssentials 
• Microsoft Exchange Server 2007 / 2010 /2013

SOLUTION

The '452 4.3.1 Insufficient system resources' error is originating from the Microsoft Exchange server due to the server either running out of disk space or free memory. To address this: 

• Increase the amount of free space on the Microsoft Exchange server drive
• Reduce the amount of memory being used by all processes

CAUSE

Usually related to back pressure, a system resource monitoring feature of the Microsoft Exchange that can detect when vital resources, such as available hard disk space and memory, are under pressure, and take action in an attempt to prevent service unavailability.  For more information please see, Understanding Back Pressure.