"Jetpack could not contact WordPress.com: register_http_request_failed. This usually means something is incorrectly configured on your web host. couldn't connect to host"
I get this message while trying to connect. NI called my host and they said everything is fine at their end and this quite a common problem with Jetpack. About HTTP and HTTPS, I am not a techie, so will just dump Jetpack till they resolve this.