I don't know when this started happening because my international orders aren't as common as US but I had a repeat international (London) customer email me today saying that she can't checkout. She has placed many orders before today with no problems.

I use USPS International Flat Rate for international shipping and this is the error she is getting on the checkout_shipping page.

We are unable to find a USPS shipping quote suitable for your mailing address and the shipping methods we typically use.
If you prefer to use USPS as your shipping method, please contact us for assistance.
(Please check that your Zip Code is entered correctly.)
I've emailed the customer asking if she's made any changes to her address since her last order but haven't heard back yet. I'm wondering if this has something to do with the rate increase and just hasn't been caught by the zen gurus yet or if I've missed an announcement.

The url to the site having the issues is http://bertsheavenscent.com .

Thanks in advance for any insight.