Just took on a client who uses SBS Server 2008. Their prior IT admin moved their email from on premises to Office 365. When the users now open Outlook they get a Security Alert: remote.xxxxxxx.com Information you exchange...The security certificate was issued by a company you have not chosen to trust. View the certificate to determine whether you want to trust the certifying authority.
When the click yes to proceed, Outlook functions properly and they receive/send email without issue all day.
How do I resolve this? It appears that Outlook is finding an internal certificate.