DownDetector said the first reports appeared around 11 a.m. ET when people could not reach ChatGPT, and the same platform also logged similar outages for Anthropic’s Claude, Google’s Gemini, Microsoft’s Copilot and Elon Musk’s xAI chatbot.

Anthropic later confirmed that Claude was fully back online at 16:16 UTC after an infrastructure issue that had affected Claude.ai, Claude Code, Claude Cowork and the Claude API. Meanwhile, OpenAI’s status page still displayed a “degraded performance” notice and added that mitigation measures had been applied.

Short, isolated outages for a single AI tool happen fairly often, but it is rare for several major platforms to fail together, which highlights how tightly linked their underlying infrastructure has become.

Because millions of people rely on these services every day, a simultaneous disruption—whose cause remains unknown—raises concerns about the reliability and resilience of the AI ecosystem.