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"The target principal name is incorrect" Outlook 2010 error when sending emails


I get the error "The target principal name is incorrect" every time when sending emails in Outlook 2010.  I completed the setup of my account using autodiscovery and confirmed I can send and receive messages in Outlook 2010.


Viewing the certificate I can see it's a wildcard cert for *  That obviously doesn't match my domain name.  How do I correct this issue so I don't get this error when sending mails in Outlook 2010?







Re: "The target principal name is incorrect" Outlook 2010 error when sending emails

Looks like you've been waiting over 4 months for your post to be answered.

I don't work for GoDaddy. But I had the same problem as you. I came across your post in my search for some answer to this problem. I don't know whether my hack will help. But here it is:

Following GoDaddy Instructions leads to this problem. Here is a copy and paste of GoDaddy instructions:

Secure SSL/TLS Settings
Password:Use the email account’s password.
  • IMAP Port: 993
  • POP3 Port: 995
  • SMTP Port: 465
Authentication is required for IMAP, POP3, and SMTP. is my domain name. is the email account I am trying to set up in Outlook.


The instructions work except for the outgoing server, if you use what GoDaddy instructions say to use, then Outlook gives you that Internet Security Warning with "target principal name is incorrect".


What I think happens is that when you send an email through the GoDaddy specified outgoing server ( in my case), GoDaddy converts the server name into the real server name. The GoDaddy instructions do not tell us what the real name is. If you can just find out what the real name is, then Outlook won't issue the certificate warning saying the principal name is incorrect.


So, to find out what the real server name is, use Outlook to send yourself an email. Answer Yes to Outlook's warning "Do you want to continue using this server?". Then, when you receive the email you sent to yourself, open the email to examine the header of the email.


To get to the header of the opened email, through the Outlook EMAIL menu, go to


    File >> Info >> Properties


At the bottom of the window that opens, see Internet Headers. The first part of my email's headers is:


Return-Path: <>
Received: from
    by (Dovecot) with LMTP id oX8+OIrluVnJOgAApeM0nw
    for <>; Wed, 13 Sep 2017 19:12:26


I bolded, italicized, and underlined the part of interest: the real server name.


You can highlight and copy the real server name.


Then close the window.


In the main Outlook that lists all the emails, in the menu, go to


     File >> Account Settings


Highlight the email you are trying to fix. Click change. [This requires that you already set up the account automatically or manually. So, the email account is already there to highlight. The account works except that Outlook keeps issuing the certificate warning.]


In the Change Account window that opens after you click "change", change the "Outgoing mail server (SMTP) to the real server name. You can paste the name that you copied.


If you click "Test Account Settings" in that same window, you should observe that Outlook does not issue the certificate warning.


This is the hack that worked for me. Maybe it will work for you and others.


Ron Lewis of Indinfer


Re: "The target principal name is incorrect" Outlook 2010 error when sending emails

IT WORKED! I changed the outgoing server from my clients domain name to following the procedure used by  indinfer NOVICE !

Re: "The target principal name is incorrect" Outlook 2010 error when sending emails

Thank You Ron for the detailed instructions.  It solved a very mysterious and infuriating issue for me.  Even godaddy support could not fix it after spending 1 hour+ with them.