I have a client that moved to Office 365 from on-premise Exchange 2010. They are using AD Sync so the old Exchange server is still online. When they open Outlook, they get a security alert for Outlook.office365.com - the security certificate for this site had been revoked. When I click to view details it shows it is issued by digicert and is valid until 8/1/2020.
This only happens when opening Outlook inside the network. laptops get this message inside the network but not outside.
Autodiscover is working properly. On the on-premise server I run Get-ClientAccessServer |select AutoDiscoverServiceInterna
lUri and it shows https://autodiscover.outlook.com/Autodiscover/Autodiscover.xml
. I can ping autodiscover.domain.com and it returns Office 365 autodiscover name
How do I stop that security alert from coming up