Hi James - welcome to the Centrify Community and thanks for posting your question. Before reviewing your info, it would be helpful to know a little more detail around your issue and configuration.
First, for any Express issues related with smart cards, we would recommend reviewing and performing cleanup steps in the following article: http://community.centrify.com/t5/Centrify-Express/Read-Me-1st-Common-OS-X-Smart-Card-troubleshooting-steps/td-p/21904
It would also be helpful to know if this is a new configuration that has never worked or was this a working configuration that suddenly stopped working? Do other users also experience the issue?
Thanks for any info you might be able to provide. Perhaps one of our other Community members has some advice to offer once more details are known.
Best regards,
-Tony