If you have incorrectly configured your Outlook 2010 email client, then the server you are connected to may show an error saying that the security certificate cannot be verified.
Step 1: In Outlook, select File and then Account Settings and Account Settings once again
Step 2: Select the email acocunt and click ‘Edit’ to change the settings.
Step 3: 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.
Step 4: We recommend using the SSL enable options with port numbers.
Step 5: Click save to apply the changes.