Outlook error (0x800CCC7C) with SMTP server error '530 denied access'
Posted by Administrator Root on 18 September 2011 06:00 PM

Outlook error (0x800CCC7C) with SMTP server error '530 denied access'

Really strange error he received in Outlook.  Outlook reports that the SMTP server requires a secured connection and is asking the user to enabled it. It even shows them where it is.  Trouble is, our server, which runs on Windows 2008 with Plesk and Mailenable, doesn't have SSL enabled.  Long story short, it turns out Mailenable has a secret deny file which can't be accessed from the GUI.


Customer complains that Outlook is returning the following error even though no configuration changes have been made server side or at the client's end:

Task 'mail.domain.tld - Sending' reported error (0x800CCC7C): 'Your outgoing (SMTP) server requires a secure connection. On the Tools menu, click E-mail Accounts, select View or change existing e-mail accounts, click Next, select the account, and then click Change. Click More Settings and then on the Advanced tab select This server requires a secure connection. The server responded: 530 ESMTP MailEnable Service, Version 0--2.53 denied access at [date] [time]'


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. The incoming IP address can automatically be added to the inbound "Access control" list if the SMTP security "connection dropping" option is enabled. The SMTP service will drop the connection when the failed number of commands or recipients is exceeded and add the IP address to the inbound "Access control" list.


  • Navigate within the Administration console to the following location: Servers>localhost>connectors>SMTP, right click on "SMTP" and select "Properties" in the menu.
  • Next navigate to the "Inbound" tab and click on "Access control".
  • 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.
  • Also set SMTP concurrent connections from 31 to something abit higher for larger companies that connect through a router.  This is to prevent them from being added to the control list again.

Alternate method to remove entries from access control list

  • In Windows Explorer, go to the folder "%plesk_dir%\Mail Servers\Mail Enable\Config".
  • Open the file "SMTP-DENY.TAB".
  • Search for the customer's IP address and remove it, then save the file.
  • Do the same in the "SMTP-DENY.SAV" file.
  • Restart MailEnable SMTP service.

That should fix the problem.

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