Microsoft 365 services including the collaboration app Teams and Azure Cloud have suffered a major outage and the company said on Tuesday it was trying to bring the services back across the impacted regions.
The company said it identified an issue "with a recent change to an authentication system".
"We're rolling back the update to mitigate impact, which we expect will take approximately 15 minutes," Microsoft 365 team said in a series of tweets.
However, the problem persisted and the company further tweeted: "The process to roll back the change is taking longer than expected. We'll provide an ETA as soon as one becomes available".
Microsoft later admitted that while the update has finished deployment to all impacted regions, "Microsoft 365 services are showing decreasing error rates in telemetry. We'll continue to monitor service health status".
The company saids it was "taking steps to resolve some isolated residual impact for services that are still experiencing impact."
This is the first major Microsoft Teams outage since the service went down back in September last year, alongside other Microsoft 365 services like Office 365 and Outlook.
Microsoft Teams users experienced message delivery delays and had issues when searching for contacts.
There are at least 115 million people using Microsoft Teams globally.
In the latest tweet on Tuesday, Microsoft 365 team said: "Our monitoring indicates that majority of the services have fully recovered. However, we're addressing a subset of services that are still experiencing some residual impact and delays in recovery".
Meanwhile, following the recently disclosed vulnerabilities in Microsoft business email servers, the hacking attempts on organisations using the services of those unpatched on-premises servers have multiplied by more than six times (or tripled) in the past 72 hours, a new report warned on Monday.
The country most attacked has been the US (21 per cent of all exploit attempts), followed by The Netherlands (12 per cent) and Turkey (12 per cent).
Most targeted industry sector has been government/military (27 per cent of all exploit attempts), followed by manufacturing (22 per cent), and then software vendors (9 per cent), according to Check Point Research.
"A full race has started among hackers and security professionals. Global experts are using massive preventative efforts to combat hackers who are working day-in and day-out to produce an exploit that can successfully leverage the remote code execution vulnerabilities in Microsoft Exchange," the researchers from the cyber security firm noted.
Amid reports indicating that about five different hacking groups are attacking the business email servers of Microsoft, the tech giant has detected a new family of ransomware.
Named as 'DearCry,' the new ransomware is "being used after an initial compromise of unpatched on-premises Exchange Servers," Microsoft said in a tweet last week. It uses the same four vulnerabilities that Microsoft linked to a new China-backed hacking group called "Hafnium".
On March 3, Microsoft released an emergency patch for its Exchange Server product, the most popular mail server worldwide. All incoming and outgoing emails, calendar invitations and virtually anything accessed within Outlook goes through the Exchange server.