strange encryption behavior
 

I am getting the following strange behavior in Outlook 2003 SP1 on XP
Pro.

I have previously received signed emails from my friend "Joe" who is in
the GAL (although his certficicate is not in the GAL) I can see his
certificate in Certificate Manager, under Other People, and it is
reported there as OK. I have also previously sent him signed and
encrypted emails successfully.

*Sometimes* when I create a new email and select Joe from the GAL in
the To field, activate the Sign and Encrypt buttons, type my message,
and click Send I get:

Microsoft Office Outlook had problems encrypting this message because
the following recipients had missing or invalid certificates, or
conflicting or unsupported encryption capabilities.

I then go to a signed email I have previously received from Joe and
reply to it, again making sure that the Sign and Encrypt buttons are
activated. That works.

Now I once again send a *new* email to Joe, as above. It now works.
It continues to work for a while, then suddenly goes back into its old
"problems encrypting this message" mode.

What is going on here?

I would prefer not putting the certificates into the GAL.

I already tried the registry modifications recommended in:


http://support.microsoft.com/?scid=k...20&sid=216#kb5

but it did not help.