The problem faced:
Accessing the MailEnable SMTP service produces an error that the connecting IP address has been "denied access".
Can be because :
The IP address of the inbound connection has been denied access in the SMTP Access Control properties of the MailEnable Administration Program or has been automatically banned because of too many subsequent invalid commands.
How can we Resolve it:
1) Navigate within the Administration console to the following location:
Servers>localhost>connectors>SMTP, right click on "SMTP" and select "Properties" in the menu.
2) Next navigate to the "Inbound" tab and click on "Access control".
3) Ensure that the Access control option is set to "granted access" and that the IP address of the incoming connection is not present within the "Except those listed below" window.
