Client Certificate Authentication EP6 SP13

Hi,

I'm trying to set up client certificate authentication on the portal. I've enabled SSL, imported the public CA certificate into the Trusted CAs (KeyStore service) in Visual Admin, and set the SSL Provider service to request client certificates & added my Trusted CA.

I've also imported my user's certificate into the browser (IE). When I go to the portal https URL, it prompts me for a certificate but the list is empty - I cannot select my certificate to log on with. Does anyone know what step I have missed, or what the problem could be?

Many thanks,

Jane