RabbitMQ + C# + SSL

Usual problem is mismatch between what you provide in Ssl.ServerName and host SSL certificate was issued for.

Also note that server-side SSL (encrypted connection between your client and server) and client-side authentication with certificate (you provide server with information which confirms that you have certificate it expects) are two different things. By providing Ssl.CertPath you intent to authorize at server using this certificate, which might or might not be what you want.