Each carrier rate you add within the app has an area that it will return rates for. When you add a carrier rate there are sections of rates, corresponding to where they are available. 

If you have a UPS Ground added to a Rest of World zone, it won't show to non-US addresses because its a Domestic rate, and only shows if the shipping address in the US. 

So double check the carrier rates you have added that you've selected the right rate for the right zone.