Outlook encrypts outgoing mails with invalid S/MIME cert - mails not readable afterwards

Dear Users,

we have OL2013 + OL2016 in place with latest KOE and latest Kopano backend. Users set outlook to encrypt all outgoing mails if pubcert is available. Randomly outgoing mails get encrypted with invalid pubcerts so neither receiver nor sender can read mail anymore.

Users report that this issue started by the time, we moved from MAPI to Active-Sync.

Can anyone relate?



Hello @plzk-de ,

since you already brought the topic up in https://forum.kopano.io/topic/754/s-mime-issue-with-outlook-2013-where-are-pub-certs-stored, maybe you want to open up a support case instead?


@fbartels it’s open since month without a real solution. Last mail from us is unanswered since +2 weeks…


@plzk-de I see a state of “waiting for customer” for this id and the last update was from our side on the 26th of october.


We did not receive any emails after 25. November. Indeed there is a reply but only visible in the portal.