I'm wondering how I can encrypt emails sent from outlook 2007/2010 using the tick box provided on the outlook client? This isn't required for all emails just certain emails that may have some sensitive information.
If I tick the box in outlook and try and send the email I get the follow error "Microsoft Outlook cannot encrypt this message because your certificate isn't valid" This just has to be for emails to an external organisation.
Is this a case of adding a certificate of sorts to my exchange 2010 server for the encryption in outlook to work? I already have OWA secured properly with a certificate.