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Hi!
I'm trying to setup reading / writing S/MIME encrypted e-mails at a customer who requires signed mails for certain workflows.
They have Office 365 with Exchange on the web, and I try to setup S/MIME with a physical PKI card in Edge.
I have installed all the necessary widgets and extensions in Edge, and I can successfully write mails.
When I try to read an encrypted mail, though, regardless if it is from me or from someone else, in the popup window the following error message appears:
The S/MIME message wasn't decrypted successfully. The ASN.1 package couldn't be opened.
I can reproduce it on our Windows 10 clients. It works on Windows 11. Unfortunately, for use at the customer only Windows 10 is approved, so switching is not a possibility. This is Windows 10 Pro with all the latest updates installed.
The same message btw. appears when I install the extension in Chrome, so it doesn't seem to be an Edge issue, more an issue with the app or the extension.
There are several people here on Technet who had the same problem in 2019, but with no solution.
What can we do here to make it working?
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Hi @Jens Hoffrichter ,
Does the error only occur to one user? Could you use IE to encrypt/decrypt mails successfully?
I have done some research on the issue and here are some solutions for your reference and hope these help.
Yes, I have that problem with multiple users in similar configured Windows installations.
We are using outlook.office.com / O365, and I would imagine that that site is automatically added to trusted sites - but I can double check.
If I try to open outlook.office.com in Internet Explorer, it opens automatically in Edge, and I have no chance of opening it in IE
Hi Jens,
I'm running some testing and experiencing the same. Were you ever able to get this resolved?
Hi Kim!
My experience with this that it is not reproducible for me when it works and when it doesn't. I have it running on some clients, but not on all clients, sometimes it works just for reading, sometimes it works just for writing. Currently I have a configuration where I can read encrypted emails in the old Outlook client, and write them in OWA with Edge....
The process is highly unstable and really unsatisfying to configure......
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Unfortunately, that thread is very specific for USAF clients, and except for looking for updates, all other solutions in there are very specific to the USAF environment.