Recently i started MS Outlook 2007 and tried connecting to a mailbox that is hosted on a mailbox server that is running Microsoft Exchange Server 2010 inside the local network. I received the following security warning “The name of the security certificate is invalid or does not match the name of the site.”

During my analysis, i found that this error had happened due to the default self-signed Exchange Server 2010 certificate – it causing a name mismatch error to occur.

Also regarding this, i found the following support knowledgebase article talks about it - this scenario applies only to Outlook clients that connect to Exchange from inside the local network.In order to overcome the problem and the article provides resolution also.

Based on the above article this issue may occur if the following conditions are true:

  • You replace the default self-signed Exchange Server 2007 or Exchange Server 2010 certificate with a different certificate.
    Note The Setup program in Exchange Server 2007 or in Exchange Server 2010 creates a default self-signed certificate when Exchange Server 2007 or Exchange Server 2010 is installed.
  • The common name on the replacement certificate does not match the fully qualified domain name (FQDN) of the URL that is stored in the following objects:
    • The Service Connection Point object for the Auto discover service
    • The InternalUrl attribute of Exchange 2007 Web Service (EWS)
    • The InternalUrl attribute of the Offline Address Book Web service
    • The InternalUrl attribute of the Exchange unified messaging (UM) Web service
By default, the URL that is stored in these objects references the NetBIOS name of the server. For example, a URL that resembles the following URL is stored:

https://NetBIOS_name.contoso.com/autodiscover/autodiscover.xml

This may differ from the host name that is used in the FQDN of the replacement certificate. For example, the replacement certificate may have an FQDN that resembles the following FQDN: mail.contoso.com

This issue causes a name mismatch error to occur. Therefore, you receive the security warning message when you try to connect Outlook 2007 to the mailbox