Microsoft said Monday that it is facing delays after it identified the cause of a major Outlook and Teams outage, and deployed a fix to the problem.

As of noon ET Monday, outage-tracking site Downdetector showed more than 5,000 user-reported problems, though this data doesn’t fully reflect the scale of the outage.

Tech outages have had dire effects around the world this year, though Microsoft’s case isn’t as widespread in comparison. In what’s been called the largest IT outage in history, CrowdStrike’s software issue over the summer halted air travel, disrupted hospitals and cost Fortune 500 companies more than $5 billion in direct losses.