Send SMTP Mail Message: An error occurred while attempting to establish an SSL or TLS connection.
One possibility is that you are trying to connect to a port which does not support SSL/TLS.
The other possibility is that the SSL certificate presented by the server is not trusted by the system for one or more of the following reasons:
- The server is using a self-signed certificate which cannot be verified.
- The local system is missing a Root or Intermediate certificate needed to verify the server’s certificate.
- The certificate presented by the server is expired or invalid.
See https://github.com/jstedfast/MailKit/blob/master/FAQ.md#InvalidSslCertificate for possible solutions.
How to solve this issue? Please help.