WorkOS change history: Radar SMS challenge failures for phone numbers in mainland China (+86)

WorkOS reported a major Radar SMS challenge outage for mainland China (+86), preventing affected users from receiving codes or completing verification. It started at 2026-10-15 17:17 UTC and was resolved at 2026-10-15 21:51 UTC, lasting 4 h 34 min; WorkOS reported recovery after its upstream provider enabled alternate delivery routes.