There is a problem with the certification for mail.contoso.com. Contact a support person or your service provider. Last tried 2 seconds ago.
The certificate from eas.contoso.com is not trusted by your phone and is invalid. Security certificate
problems may indicate an attempt to fool you or intercept any data you share with the server.
We recommend you do not continue to connect to this server.
Do you want to continue syncing information anyway?
Accepting the untrusted certificate allows the client to establish an SSL session based on the Thumbprint of the server certificate. Updating the server certificate changes the Thumbprint, and this causes the connectivity failure.
To work around this issue, perform a hard reset of the profile on the Windows 8 mobile device, or reconfigure the ActiveSync profile for the user.
Article ID: 2970372 - Last Review: 1 Oct 2015 - Revision: 1