new certificate does not work with thunderbird (old one worked just fine)

The certificate I was using from comodo for the last year just expired.

No problem; I filled out the form, got a new one into firefox, saved it out to a file, imported it into thunderbird, told thunderbird to use the new certificate. Life is good, I thought. I then sent signed emails to friends so that they could send encrypted emails to me (they had been doing so before my cert expired). (Indeed I also sent encrypted emails but I don’t think that is relevant.)

Alas, my friends tell me that they get a pop-up that says
“You specified encryption for this message, but the application failed to find an encryption certificate for” (ie, my actual email address, not johndoe’s :wink:

However, when they go into the advanced tab and view certificates the new cert is right there.

One thing that has been noticed is that

  • my old cert had a “Issued To CN” of my name and an “Issued To OU” of Comodo Trust Network PERSONA NOT VALIDATED
  • in my new cert these fields are blank

Thoughts? Suggestions?