We've got a proper DigiCert wildcard certificate which appears to be set up properly on Exchange 2007.
The Microsoft test site https://www.testexchangeconnectivity.com/ passes without any problems as does Test-OwaConnectivity & Test-OutlookWebServices internally.
Our problem is that internal Outlook users keep getting a message asking if they'd allow Autodiscover to configure Outlook and then a popup asking for credentials. If the user ticks a box to allow the autodiscover service to configure Outlook always, they still get the popup every time they open Outlook.
Any ideas?