free comodo certificates not recognized by outlook

hi all,
I can send/receive signed emails to/from email box associated with comodo certificates thru SecureEmail home version.
OK! good.
But when i send signed mails to my professional box on exchange server using outlook 2007 mail reader, outlook always says that certificate is invalid!!!

any help?
is this normal (because free certificates) ?
(testing with thawte free certificate is correct…)

best regards
french guy


Can you please submit the ticket in the following link

After installing free Comodo Secure e-mail for personal use, i am unable to receive or send secure (encrypted and digitally signed e-mail messages. My Outlook Express version 6 detects a problem and shuts down? how do i resolve this issue?


Please submit the ticket with error screen shot in the following link