I am receiving this error in my listserv.log file:

452 4.3.1 Insufficient system resources (UsedDiskSpace[C:\Program Files\Microsoft\Exchange Server\V15\TransportRoles\data\Queue])

 

Most everything I find seems to point to the exchange server as the problem. However, is there any other possibility it is something in listserv? I have 35G free on the disk, and almost all the ram is free.