"We encountered an error trying to access your server at https://www.e-junkie.com/gc/XXXXX/ResponseHandler.php -- the error we got is Send failed with code: 500."

If your Google Checkout payments are resulting in this error message after checkout:

We encountered an error trying to access your server at https://www.e-junkie.com/gc/XXXXX/ResponseHandler.php -- the error we got is Send failed with code: 500. Response body was:

Please double-check every step of our Google Checkout integration procedure to confirm you haven't overlooked anything -- especially note our API Callback URL and Callback Method requirements, and make certain that you do not enable any Advanced settings.

• Questions?
  Feel free to contact us if you don't find an answer in our Help pages or our Forums.
  
  If you just want to enquire about what all E-junkie does, you can check our feature list.