Google’s popular web-based email service Gmail went dark for millions of users on Monday. The outage was short-lived, about 40 minutes, but it also affected related online services like Google Drive and the Chrome web browser. And although Google’s initial silence triggered concerns that the firm’s services were electronically attacked, that’s not the case at all.

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“We are currently experiencing an issue with some Google services,” a Google spokesperson confirmed during Monday’s outage. “For everyone who is affected, we apologize for any inconvenience.”

Initially, there were reports that Google was suffering from a Denial of Service (DoS) attack. But Google denied those reports and there is no evidence that such a thing occurred.

Two hours later, the firm’s Google Apps status dashboard was updated with a partial explanation. “The problem with [Gmail] should be resolved,” Google reported. “On Monday, we experienced an issue with Gmail and some users experienced slow performance or errors … Although our engineering team is still fully engaged [in an] investigation, we are confident we have established the root cause of the event and corrected it.”

Finally, Google engineer Tim Steele offered a more definitive explanation, noting that it was a “server-side problem.” He wrote in a Google support forum that the issue was with a service called Chrome Sync Server, which had been misconfigured with “a faulty load-balancing configuration change … That change was to a core piece of infrastructure that many services at Google depend on. This means other services might have been affected at the same time.”

That’s right. It was just human error. Sorry, cloud computing doubters.