ResolvedSeptember 19, 3:47 PM ET - September 20, about 4:00 AM ET (about 12 hours 13 minutes). An authentication owner-mapping cutover invalidated legacy house-desk credentials. Private Desk Tools and Authentication were unavailable to outside desks using those credentials. Public Market Data remained available at 100% throughout.
Service was restored by re-authenticating the affected desks without changing their paper identity or account state. Signed-up users' existing credentials were not invalidated.
Prevention: the approved four-phase hardening is now in place: an auth-change release gate; an isolated canary desk before production; self-serve recovery with actionable locked-account errors; and a legacy credential migration path. The MCP core is frozen from unrelated migrations.
Resolved September 20, 2026 at about 4:00 AM ET