forwardGeocode can't find certain locations

Hi, I’m using Native Geocoder’s forwardGeocode to get latitude and longitude of zip codes. It works fine for some zip codes (like 75075 which is Plano, TX) but when I search for some zip codes like 75002 (which is Allen, TX), I get the infamous “Cannot find a location” message.

Any idea how to resolve this?


I noticed that some US zip codes are used in other countries as well (75002 is for Allen, TX as well as Paris, France!), so I have to specify the country in the geocoding.
Anyone know of another way of detecting the user’s country? I’d rather have it auto-detected rather than the having the user pick from a dropdown.