Forum Discussion
Outlook - Certificate has been revoked
If you're having certificate warnings in Outlook for an on-prem Exchange deployment you should post a screenshot here so we can see exactly what the warning says. There's a number of potential problems and solutions for certificate issues.
Here is the error message (Office 365):
Can this be related to this?
https://support.office.com/en-us/article/Office-365-URLs-and-IP-address-ranges-8548a211-3fe7-47cb-abb1-355ea5aa88a2
I see addition of http://crl4.digicert.com/DigiCertCloudServicesCA-1-g1.crl in Office 365 Certificate Revocation List (Root URLs)
Amir Jafarian that looks like either a problem communicating with the CRL or there might be another issue with your system or an intermediate network device (like a proxy). Since you are connecting to Exchange Online you can raise a support ticket with Microsoft for troubleshooting assistance. You can also try running diagnostics with the SARA tool (https://diagnostics.outlook.com).
Other posters are complaining of certificate popups for on-premises Exchange server environments, which could be an entirely different problem with their server or certificate configuration.
any news with this
