If you are seeing any spontaneous problems with USPS-based Shipping calculation (unrelated to any settings you may have changed or created in E-junkie Admin recently), this notice from USPS support may explain the matter; unfortunately, there is nothing we can do to improve the situation, as this is a problem at USPS's end where their system is occasionally failing to respond to our (and other sites') requests for a rate lookup. Hopefully, they will resolve their issues forthwith.
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http://www.usps.com/homearea/onlinesysteminterruptions.htm
The Postal Service continues to experience intermittent system interruptions in our Webtools API’s. We apologize for the inconvenience this is causing, especially at what is one of the busiest times of the year. We are hopeful that full service, across the country, will be restored as soon as possible. We thank you again for your patience.
We have taken every step to resolve the situation, and continue to work around the clock both internally and with our external partners.
We appreciate your business and your patience.
Internet Customer Care Center
