Email Client: Microsoft Outlook 2010
Error Message: The server you are connected to is using a security certificate that cannot be verified. The target principal name is incorrect. 


Solution: This error is caused by a mismatch in enabling SSL and your port number in your account settings. Open Account Settings in Outlook and click on the advanced tab. If you need further assistance to open your account settings please see our Outlook 2010 Accessing Account Settings guide.


Verify that you are using the correct ports for the incoming and outgoing mail server. If you are going to use the SSL enabled settings you will need to use the correct servers. If you are on a shared hosting plan, you would use: (you will need to replace the ## with the server number in your Temp URL)

We recommend using the SSL enable options. If by chance you are in a school or somewhere that may have these ports blocked, you can use the non-ssl settings. The correct ports are below:

Important! To get your SSL settings please see our article on Getting Started Guide: Email.

Non-SSL incoming POP: 110

Non-SSL incoming IMAP:  143

Non-SSL outgoing SMTP: 587

SSL enabled incoming POP: 995

SSL enabled incoming IMAP: 993

SSL enabled outgoing SMTP: 465

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n/a Points
2014-05-01 7:45 am

The port details are correct, but still the same error is seen. "The server you are connected to is using a security certificate that cannot be verified. The target principal name is incorrect”.

Secondly when I clicked “view certificate”à it shows issued to and the same settings are done in incoming and outgoing  account settings. Also the certificate status says” The certificate is OK.”.

I tried all trouble shooting including system restore…but nogo. Your help in this regard is highly appreciated.

10,022 Points
2014-05-01 7:58 am
If you're using a hostname which is not covered by the SSL certificate, this warning will appear. Could you clarify the hostname that you are using within your incoming/outgoing mail server settings?
n/a Points
2014-05-01 8:21 am


Hi JeffMa,


Good to see your quick response. Here are the details requested.


E-mail Client: MS outlook 2007


OS: Win XP SP3


Incoming mail server:


Port: 993, SSL type


Outgoing mail


Port: 587, TLS type


Secondly when I try the test account settings button, it says its successful and I receive a test mail too.


10,022 Points
2014-05-01 9:23 am
Unfortunately, I don't have exact details on why you may be getting this error in Gmail, but you may attempt to permanently save the exception. The Gmail forums may have more information for you as well.
n/a Points
2014-08-08 1:37 pm

From "Outgoing Server" Uncheck My outgoing Server(SMTP) Requires Authentication.

it worked for me :)

n/a Points
2014-09-10 6:21 am

I've been searching the web for an answer to this very problem, but with my local provider and using Outlook 2013 - POP/SMTP. The above replay gave me the hint:

There was nothing wrong with the names, but I found out that in the advanced settings of the account  for " Use the following type of encrypted connection" I had set "Auto". When set to "none" the problem disappeared!

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