When the guessCarrier or stating UPS as the carrier it errors out because it's not the normal 1Z for UPS. I have a valid tracking number that when put in the UPS site works fine but not with shipit:
https://wwwapps.ups.com/WebTracking/track?track=yes&trackNums=802269919937015457
Can you please add support for UPS to detect tracking numbers starting with 802 and also if called directly?
Thanks!