SOGo stores recipient certificates in the address book. Is there an address book entry for the intended recipient and if yes, does it show an S/MIME certificate?

Which SOGo version are you using?

The contact is in the address book. But the S/MIME certificate is not displayed for it. Should he be shown?
However, the S/MIME certificate is successfully sended with a signed message.

SOGO 4.3.2

2020-09-14 12_41_23-SOGo.png (7,297 bytes)   

2020-09-14 12_41_23-SOGo.png (7,297 bytes)   

Whenever you open a signed message, SOGo looks for the "From" address in the contacts of the current user. If a matching contact is found, it stores the certificate in this contact.
The only exception is that the "From" address must not be one of the current user's own sender addresses.

I'm also running SOGo 4.3.2 - works here...

Yes, I understand how it should work.
It seems that SOGo just doesn't save the certificate for the user.
Could you send a screenshot of the user card with the certificate?

Sure

Thanks!
I checked. Indeed, for some contacts the S/MIME certificate has been added.
But SOGo still doesn't add the S/MIME certificate to the contact card when receiving a signed mail. I've tried different browsers, tried to restart iRedMail... Unfortunately, no result.
I can't figure out what it might depend on..
Any ideas?

Looks like private notes aren't visible to you: Could you share the mail or send a copy to me (sogo@schmirler.de), so I can take a closer look?

Same here with Version: 5.0.1.20201121-1

Receiving signed message, It has the green star saying messsage is signed, but it does not store this signature from the From: sender. SO it is impossible to reply back and send encrypted e-mail.

image.png (39,120 bytes)   

image.png (39,120 bytes)   

Also please not that this was working a few versions before (still 5), not sure which one specifically

Found that there is an error in sogo.log:
Nov 21 11:09:24 sogod [1187212]: [ERROR] <0x0x55b417d6ce90[UIxMailRenderingContext]> found no viewer for MIME type: application/pkcs7-signature

@edrimon
Try adding the same email address (for the contact from whom you receive the S/MIME signed message) to email address 2. i.e. the contact card must have 2 identical email addresses.
It works for me.

You mean something like the attached? still doesn't work..

image-2.png (49,406 bytes)   

image-2.png (49,406 bytes)   

image-3.png (26,054 bytes)   

image-3.png (26,054 bytes)   

Yes, right. Try sending the S/MIME signed message again. After that, reply S/MIME signed mail and then check the contact.
SOGo adds S/MIME signature after sending a reply.

Really thank for replying, I will try that, the thing is that for every new e-mail that I get signed and I do not know a priori their e-mail address, I have to do this manually and then send back again a signed message to them, asking them to resend the e-mail in order to have the S/MIME working.. It does not sound so good, actually not so realistic..

Yes, SOGo is not perfect. While.
Outlook works perfectly with S/MIME.

Thanks, noted. Thunderbird and Horde as well..

Just if it helps, it seems working in case I double save the sender's e-mail in the personal address book, it does not work at all if the sender is in the global address book. Thanks again..