TCP monitor vs TCP Half Open

You are most likely getting the SSL failure because with a TCP monitor you complete a full three-way handshake. Since you are using a TCP monitor against an SSL interafce it then tries to initiate the SSL handshake and fails. TCP Half-Open doesn't complete the three-way handhsake since it sends a RST instead of an ACK, so it never attempts the SSL handshake. So, in short the TCP vs Half-open will only give you the knowledge that a full TCP handshake can occur vs it responding on the port.