Cron Job "Failing" but returning status code "success"

I'm working with the Freshbooks API and I'm getting

<?xml version="1.0" encoding="utf-8"?>
<response xmlns="http://www.freshbooks.com/api/" status="ok"/>

For whatever reason I'm getting 60 emails with just this as the body. My Cron code looks like this:

curl -sS http://example.com/update开发者_开发技巧_billing

I have no idea what I'm doing when it comes to this, so I'm not sure if this is enough information, but I'm obviously doing something wrong because the Cron kicks off 60 times. Let me know if you need more information.

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cron will mail any output a program generates to the user, so unless you tell curl not to put something on stdout (eg by redirecting to /dev/null or a file you want to analyze later on in the script, or by using the -o - --output option) cron will send you a mail.