Claude, ChatGPT and xAI’s Grok were gradually recovering on Thursday after a technical issue disrupted Microsoft Exchange Online and several other Microsoft 365 services worldwide.

The disruption affected access to multiple online platforms. According to reports, outage-monitoring service Downdetector recorded widespread problems involving the three major AI assistants.

Meanwhile, reports also indicated issues with Google Gemini. However, Google had not confirmed the reported disruption at the time of publication.

Microsoft Identifies Authentication Issue

Microsoft initially said it had identified a common failure pattern involving authentication and protocol connectivity within Exchange Online.

The company later traced the problem to a core authentication configuration used by several internal services within the Exchange Online infrastructure.

Microsoft engineers manually tested individual servers before expanding corrective measures across the affected systems.

“We continue to see gradual improvements to the service as our mitigation actions are applied,” Microsoft said in an update.

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However, the company warned that some users could continue experiencing service disruptions and delayed emails while recovery work continued.

Several Microsoft Services Affected

The disruption extended beyond Microsoft’s cloud-based email and calendar platform.

Reports indicated that OneDrive for Business, SharePoint Online, Teams, Microsoft Purview and Microsoft Defender XDR also experienced problems.

Consequently, the outage had the potential to affect businesses that rely on Microsoft 365 for communication, collaboration, cloud storage and security services.

Microsoft continued applying mitigation measures across the affected infrastructure as engineers worked to restore normal operations.

AI Platforms Also Report Disruptions

The outage also coincided with reported disruptions involving several leading AI platforms.

Claude’s status page showed service issues affecting some of its models, while other reported problems had already been resolved.

At the same time, Downdetector recorded thousands of user reports involving AI services. However, the platform’s figures represent reports submitted by users and do not indicate the total number of people affected.

The simultaneous disruption across widely used digital services highlighted the interconnected nature of modern cloud infrastructure.

For users, service availability was expected to improve gradually as Microsoft completed its recovery measures.