Four Major AI Services Suffer Rare, Overlapping Outages

ChatGPT, Claude, Gemini and Grok all experienced reported service disruptions during the same Thursday-morning window, an unusually overlapping failure across four prominent AI services. OpenAI and Anthropic later marked their incidents resolved, but Grok was still displaying a user-facing error when Ars Technica published its account.

Anthropic was first to post a partial-outage notice, reporting elevated request errors for Claude Mythos 5.1, Claude Fable 5.1 and Claude Opus 5 at 9:23 a.m. Eastern. It said it identified the cause about 15 minutes later, deployed a fix and resolved the incident at 12:16 p.m.; a separate brief error period affected Claude Sonnet 5 shortly after noon.

OpenAI reported degraded performance from elevated errors across ChatGPT and Codex at 10:43 a.m. It deployed a mitigation a little more than half an hour later and marked the incident resolved at 12:55 p.m.

Grok remained affected later in the day. Its service presented users with an error saying it was experiencing issues and that xAI was working to restore service. User-submitted Downdetector reports for Grok rose from fewer than 10 shortly before 9 a.m. to 1,365 by 9:45 a.m., before falling later.

Gemini is the least conclusive case. Google had not publicly acknowledged a problem, but Downdetector reports rose from roughly 23 to 412, and StatusGator recorded what it called a likely Gemini API outage between 10:45 and 11:15 a.m. The signals support a reported disruption, not a confirmed account from Google of its scope or cause.

The timing was striking, but it does not by itself show a common failure. Amazon Web Services, Microsoft Azure and Cloudflare had not reported major issues at publication, although user issue reports for all three rose somewhat that morning. Anthropic and OpenAI posted incident responses, but no shared cause had been identified.

The disruption also drew jokes about how much work and attention now run through chatbot interfaces. That reaction is cultural rather than evidence of operational impact, but it accompanied an incident that was rare by the providers’ published reliability figures: Claude reported 99.4% uptime over the preceding 90 days, while OpenAI reported 99.63% for ChatGPT and 100% for ChatGPT Codex over the same period.