Hello,
I have renamed the heading because since version 8965 errors occur not only when sending but also when receiving mails that are signed with an S/MIME certificate.
Receiving mails
When receiving mails that have been signed by the sender with an S/MIME certificate, I receive an error in every tested client and it is also displayed incorrectly in Webmail.
Error message in Outlook
Error message in emClient (Version 10.1.4588)
Incorrect display in Webmail (missing fingerprint symbol)
Correct display in Webmail (before SM version 8965)
Sending mails
The problem is that mails signed with S/MIME in Outlook arrive at the recipient with the following error “The digital signature of this message is invalid or untrusted”.
After some tests I noticed that Outlook writes the content Content-Type: in two lines. SM changes this to one line and this is where the error comes from.
This error does not occur when sending via em-Client, as this writes the Content-Type content in one line.
Since I can't get any further with the support, my question is whether others here in the forum have observed the same problem.
My configuration: Windows Server 2022 (German), SM Server Version 9091, Outlook 2021 (German), Outlook 365 (English), IMAP and MAPI connection
Best regards
Oliver