Users are getting “Security certificate on server is not valid” error message when trying to access emails from their mobile devices ...And you just recently has renewed the CAS & ISA 's Verisign certifcates

UPDATED 02/15/2011

I know I know...is not new, ours Verisign friends have published new Intermediate certificates, so all new or renewed certificates requested at (10/30/2010)  with all possible path set, will need to update or install this Intermediate certificate in the servers, in mobile devices and clients machines as well..

SSL/TLS certificates issued by VeriSign after Oct 10th 2010 will use a trust chain that includes the new intermediate certificates. You may need to import these certificates into CAS and ISA Server to support TLS with partners.
If you use VeriSign for your TLS certificates, I believe you need to import these new intermediate certificates before importing any newly requested VeriSign TLS certificate
See the link http://www.verisign.com/support/verisign-intermediate-ca/secure-site-intermediate/index.html

If you enrolled for your certificate between May 17, 2009 and October 10th, 2010 Click here for your Intermediate CA

If you enrolled for your certificate before May 17, 2009 Click here for your Intermediate CA

Download the root CA for Windows XP SP3 http://www.microsoft.com/downloads/en/details.aspx?FamilyID=25249786-2b8e-4c51-8f4b-727ce25cc2c5


Please follow this link for how to install this certificate in Windows Server environments https://knowledge.verisign.com/support/ssl-certificates-support/index?page=content&id=SO8227

Enjoy

-Dario