Is the loopback address reachable on the network you are connecting from?
When you ping and trace route to the loopback address does it respond to ping and go the expected direction.
For self traffic you don't normally need a security policy but if you do setup policies for self traffic you would use the junos-host zone as the to-zone to establish the restrictions. Without a junos-host policy the services / protocols enable on the zone host inbound services are simply allowed from everywhere.