On Thursday morning, multiple AI assistants under OpenAI, Anthropic, and xAI experienced service disruptions. Some users were unable to log in, initiate requests, or receive responses. The affected products included ChatGPT, Claude, Grok, as well as certain developer tools and API services. The relevant companies subsequently restored their systems one after another.
Many users on social media have stated that service interruptions have directly affected their daily work, involving tasks such as writing, data retrieval, programming, and code assistance. This also reflects that generative AI tools are increasingly becoming an integral part of office processes.
OpenAI has the highest number of errors.
On the third-party troubleshooting platform Downdetector, the peak number of complaints related to OpenAI was approximately 38,000 times, which is significantly higher than that of the other two platforms. Looking at the types of issues marked by users, about 80% were directed towards ChatGPT, with some also concentrated on Codex and the application side.
At 10:43 a.m. Eastern Time, OpenAI stated that they were investigating the high error rate issue affecting ChatGPT and Codex; at 11:17, they reported that mitigation measures had been taken and continued to monitor the recovery situation. By around 12:55 p.m., the related fault was indicated to have been resolved.
Anthropic Two times of fault handling
The status page for Anthropic displayed that at 8:37 a.m. Eastern Time, there was an increase in error rates for Claude Sonnet. Approximately 19 minutes later, it was marked as resolved. Subsequently, at 9:26, a second incident occurred affecting multiple Claude models.
Anthropic indicates that the team has identified the cause and deployed a fix, and the incident ended at 12:16 PM, although the specific reason was not disclosed. A company spokesperson stated that this infrastructure issue led to partial interruptions in Claude.ai, Claude Code, Claude Cowork, and Claude API.
Grok web end and API affected
xAI also confirmed that there were temporary outages on the web version, mobile version, and services within the X platform of Grok, as well as in two API regions in the United States. The company stated at 9:30 a.m. Eastern Time that they are investigating the issue and working to restore service. The peak number of complaints on Downdetector was around 1400.
According to the times disclosed by each company, ChatGPT, Codex, Claude, and Grok resumed around 12:55 PM, 12:16 PM, and 1:07 PM Eastern Time, respectively.
Additional information:As of now, the weekly active users of ChatGPT have exceeded 1 billion; the monthly active users of Claude are around 300 million; and as of March 2026, the monthly active users of Grok are approximately 117 million.
