Microsoft’s new Office 365 cloud-based service took a hit this week when customers were unable to access email and other programs for about three hours on Wednesday. As we noted at the time, Microsoft can’t really afford to lose customers as it engages in an intensely important battle with Google’s own cloud-based set of applications.

Now, Mary Jo Foley at ZDNET has uncovered an email that Microsoft has sent to customers apologizing for what happened, citing a networking disruption at a North American data center. It also indicates that those who were impacted will receive 25 percent off their monthly bill.

“The data center’s networking facilities have been remediated and we are investigating the root cause,” the note says.

The company also said that it attempted to keep a steady stream of communication with customers who were experiencing problems with the service, perhaps learning from some of the heat that Amazon.com took earlier this year after its cloud services platform went down.

The email doesn’t get into specifics about what occurred, but one of Foley’s sources said that Cisco networking gear failed. The company declined to comment on the cause of the outage when contacted by GeekWire.

But they did provide this statement about the credit.

“We have been reaching out to the impacted customers and will proactively provide impacted customers with a 25 percent credit on a future monthly invoice.”

Office 365, which debuted two months ago, features online versions of Exchange, SharePoint and other Office products.

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