Microsoft is having worldwide problems with its cloud software, which has seen some people locked out of its Office 365, Outlook and Teams products.
The company blamed a recent code change to its Azure Active Directory service, which manages user identities, for the outage, which began around 11am.
The company said the problem was non-regional - Microsoft-speak for "global".
"We've identified a recent change that appears to be the source of the issue," it said via Twitter around midday NZ Time.
"We're rolling back the change to mitigate impact."
The company performed the rollback. Howerver, it does not appear to have fixed the issues.
"We're not observing an increase in successful connections after rolling back [the] recent change," it said.
The company's most recent update, at close to 2pm NZT, indicated it was making progress.
"We've rolled back the change that is likely the source of impact and are monitoring the environment to validate that service is recovering. Please visit http://status.office.com for additional information on this issue," Microsoft said.