Outlook certificate alert

Frequent Contributor



Our SSL certificate is expired today, but we renewed it two days ago. 


Today, Outlook pops up a security warning for all user saying "The security certificate has expired or is not yet valid." I clicked the "View Certificate" button, it shows the old certificate.


I checked the local computer certificate store and found the old certificate is in the trusted store, I removed it, but it didn't help. Outlook still remembered the old certificate. 


OWA is fine and the certificate is updated.


Need help!


Thanks in advance!

1 Reply

What was that certificate used for? Exchange? AD FS? Have you made sure to update it on all relevant endpoints? Removing it from the local store doesn't make a difference if Outlook is hitting a server with said certificate still installed.