Claude chatbot runs into temporary problems

Anthropic posted an incident report on September 22, 2026, saying three versions of its Claude chatbot were having problems. At 00:57 UTC, it said requests to Claude Mythos 5.1, Claude Fable 5.1 and Claude Opus 5 were returning errors, like calls not going through. By 01:17 UTC, it had found the problem and was working on a repair.