Plugin blocks national shipping option

Hello,
I have been successfully using you plugin for local deliveries for my flower shop, but I am now having trouble adding the option for national shipping for items that aren’t perishable.
I have added a second shipping zone by typing in the name of the country and setting a flat rate, but this options doesn’t show up at checkout for addresses outside the map that I’ve drawn for deliveries. Instead I get the error “no shipping methods available”.
National shipping only works when I disable your plugin.
I was wondering if this is a problem that would be solved using the premium version of the plugin and if you have any suggestions to solve this issue.
Thanks!