I have observed your requirements and request you to please visit the following thread for your kind reference as it seems similar to what you require.
I have gone through the above reference post and I am also facing the same issue when we connect to an IMAP server that requires an SSL connection.
And you recommended to use the below property to assign the client certificate
X509CertificateCollection EmailClient.ClientCertificates { get; }
Some one replayed in the above post that " The certificate is installed on the email server , you shouldn’t load the certificate from the client certificate store."
Can you please confirm my understanding is correct,
Server Certificate is installed in the email server
Client Certificate need to install on my machine
In the C# code, Load the client certificate and assign to the property X509CertificateCollection EmailClient.ClientCertificates { get; }
I have observed your requirements. An issue with ID EMAILNET-39687 has been created in our issue tracking system to further investigate and resolve the issue. This thread has been linked with the issue so that you may be notified once the issue will be fixed.