If the SMTP logs shows the following error:
530 mail.domain.com ESMTP MailEnable Service, Version: 1.986-- denied access
Please refer to the steps mentioned below:
1.From the Windows server, open the Mailenable.
2.Go to the following location from Mailenabl: Servers>localhost>connectors>SMTP, right click on "SMTP" and select "Properties" in the menu.
3. Under the "Inbound" tab and click on "Access control".
4. Make sure 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.