Google announced on Tuesday that a "rare" network failure is responsible for the long email delays experienced earlier this week by many Gmail users.
Google, which apologized to users for the unexpected delays, said the issues were caused by two network failures occurring at once.
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"The message delivery delays were triggered by a dual network failure," Google said on its official blog. "This is a very rare event in which two separate, redundant network paths both stop working at the same time."
The network failures were unrelated, but the combination caused Gmail messages to start piling up.
The impact on users varied, according to the company. Most messages were unaffected — 71% of messages had no delay and of the remaining 29%, the average delivery delay was 2.6 seconds. But 1.5% of messages were delayed more than two hours, which means 1.5 out of every 100 sent messages didn't arrive on time.
"Users who attempted to download large attachments on affected messages encountered errors," Google added. "Throughout the event, Gmail remained otherwise available — users could log in, read messages which had been delivered, send mail, and access other features."
Google said it is taking steps to make sure it is back up to capacity.
"We also plan to make changes to make Gmail message delivery more resilient to a network capacity shortfall in the unlikely event that one occurs in the future," Google said. "Finally, we’re updating our internal practices so that we can more quickly and effectively respond to network issues. We’ll be working on all of these improvements and more over the next few weeks."
Image: Google