java.net.SocketException: Connection reset -- Make sure you select a port with SSL

I'm having an issue configuring Usage Meter 3.6.1 to a vCenter server.

Port TCP 443 is open from UM to the vCenter server and the vCenter server certificate is valid and the hostname I am using in usage meter is in the SAN of the SSL certificate

This is the full error:

• There was a problem checking the certificate for HOSTNAME:443. java.net.SocketException: Connection reset -- Make sure you select a port with SSL

Many thanks