How do I import the security certificate to Out

How do I import the security certificate to Outlook 2007?

I read this first but it doesn’t tell me how to import to my mail which is Outlook

Hello Judith,

Are you trying to import the AVG certificate?

yes, I just started getting a message.The server you are connected to is using a security certificate that cannot be verified  The target principal name is incorrect.


Judith, please open your Outlook application > File > Options > Trust center > Trust center settings > Email security > Import. This will import the certificate. 
Keep us updated on the progress.

Hello Judith,

Are you trying to import the AVG certificate?

Thank you for confirming, Judith. 
Please have a look at this article: https://support.avg.com/SupportArticleView?urlname=AVG-Troubleshoot-invalid-email-certificate and check if that helps.