Google, which first acknowledged the outage at 11:12 a.m. Pacific Time (1412 ET), said a little over an hour later that the problem with Gmail had been resolved.
As of late Friday, the company did not offer an explanation for the outage, which affected users in at least India, Britain and the United States and prompted a stream of complaints on Twitter from users in many more countries.
"We're investigating reports of an issue with Gmail. We will provide more information shortly," the company said on its "App Status" dashboard online, which tracks the state of various Google services.
Google Docs, the cloud-based productivity application that competes against Microsoft Corp's Office suite, also suffered a service disruption, according to the Google dashboard. Other Google properties, the social network Google Plus, and YouTube, appeared to load slowly as well.
Gmail, which includes calendar and chat features, has soared in popularity over the past decade to become one of Google's most successful product offerings. With more than 420 million users, it has begun to make small inroads against Microsoft Exchange in the battle to provide email services for corporate customers as well as individual consumers.
Yahoo Inc, which also runs a rival Internet mail service, seized the moment to post a screenshot of the Gmail error page to Twitter. Yahoo later apologized for the barb and deleted the tweet.
Google users attempting to sign on saw a "temporary error" message and a brief note: "We're sorry, but your Gmail account is temporarily unavailable. We apologize for the inconvenience and suggest trying again in a few minutes."