I have a user that received a digitally signed email and he would like to begin exchanging encrypted email with the sender. The red certificate ribbon displays in the upper right corner of the opened message and everything checks out ok in the details of the certificate. When I try to add the sender to the user’s contacts and save the certificate there isn't one under the certificate button. I've tried adding it manually but the sending or receiving of encrypted mail fails. Another user within my organization received a digitally signed email from the same sender and successfully added the certificate through the "save contact" button. I've since had the sender send digitally signed messages to several other people and the problem seems to be about 50/50. Some can see the certificate but others can't. All users are on Outlook 2007 and an exchange server is being used. Thanks!