Hi,
Are you using the latest HikaShop version ?
Did you activate the debug mode on the UPS plugin ? It is possible that your credentials are wrong or an error is pushed but, if the debug mode is not activated, the trace wouldn't be displayed.
Zone is not really required for UPS because the plugin would retrive the address of the current logged user.
You have to check that your customer have a right adresse and yhat your united states country is a valid one (with right 2 & 3 letter codes).
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.