A number of Yahoo Mail users abruptly lost access to their email on Monday night. Two days later, the outage is still ongoing, and customers are growing extremely frustrated with the extended downtime. The company has acknowledged the issue on Twitter, and now SVP of communications products Jeff Bonforte has issued an apology at Yahoo's official blog. The outage stems from a problem in one of Yahoo's mail data centers, Bonforte says, though he doesn't offer any other details on what went wrong. "The issue has been harder to fix than we originally expected," he concedes. "We have dozens of people working around the clock to bring it to a resolution." Yahoo now estimates that it will restore inbox access for all affected users by 3PM PT (6PM ET) today.

As their unintentional email hiatus stretches on, some Yahoo customers are lambasting the company for its lackluster updates on the situation. Email is an essential tool for most anyone that browses the web, and Yahoo's scattered attempts at communicating the problem have been met with hostility and disappointment. It's also difficult to gauge just how many users have been impacted by the outages. Even when Yahoo Mail is up and running, some users remain unimpressed with the Flickr-inspired Mail redesign that debuted in October. For them, the nicer aesthetics haven't been worth the tradeoffs; Yahoo's most recent iteration of Mail eliminated tabs.

Update: According to Yahoo, email service is now back for "most" users using their web browsers, iOS, Android, or Windows 8. The company is still working on restoring POP and IMAP access, so those that use an email app on their computer, for example, may still be out of luck.

The fortunate individuals who do have access should be able to log into their accounts and send and receive new messages, but emails sent between November 25th and December 9th may be missing from their inboxes altogether. Yahoo says that is is working on restoring the messages and remaining functionality, and will continue to update its status page with further updates.