IMail - SMTPD 'denied access' error

Question/Problem: I am seeing the error message below in my SMTP logs. What does it mean?
Denied access from 1.2.3.4

Answer/Solution: This means that you have 1.2.3.4 (or a range that includes 1.2.3.4) entered in your SMTP Security | Control Access list. Therefore, this IP address is prevented from connecting to your SMTP service. More information about the SMTP Control Access list can be found in the IMail User's Guide:

IMail Server 8.2 User's Guide - Setting Access to the SMTP Server