@Dons2000 wrote: I'm getting a pop up error message when I open Outlook (Office 2016) to view my TPG emails. This started today.   The pop up warning states; "The server you are connected to is using a security certificate that cannot be verified. The target principal name is incorrect.". When you view the security certificate, it indicates it is issued to "mail.wondercom.com.au" , not TPG, and expired 7/05/2017.   According to web searches, "Wondercom" appears to be some kind of old subsidiary business of TPG. visit official website If that is the case, why is TPG all of a sudden today, using a subsidiary business' expired security certificate on TPG's mail server????   This needs to get fixed now.  mail certificate message.jpg ‏110 KB  by the moderator has SSL turned off which I think means that mail is sent and received in clear text.  ... View more