Hello So have an app that run as a Windows Service, which will send a mail that is Encrypted and Digital Signed, When i run unit test and send the mail everything works fine. but as soon as i do end to end test and use the windows service to send the email, it send the mail but when the other user gets the email is not signed at all. I was wondering if any has any pointer or has experience this issue before

Hi, Windows Service is running under "Local System" user by default, so your service couldn't access your default user certificates storage. You should put your certificates to Machine Store or a pfx file(signing), cer(encryption).

You can email to support@emailarchitect.net for support directly.