Hi @aboyling . Is this still a problem?
Is there any further info displayed regarding the certificate details.
Do you normally use Outlook with security enabled or did it reinstall with security enabled by default?
@aboyling . Setting security is where you set up the email connection. The incoming and outgoing server should be mail.tpg.com.au. Try Security=None to check Outlook is working. Then put security back on. Installing Outlook might have loaded an old certificate.
@aboyling . This link has a post with links to versions of Outlook and Android mail client (near the end by Shane).
The security setting I mentioned is in the section where you put mail servers, port numbers, userid, etc. If you are able to save security=none setting, then I don't know where the certificate is needed.