1. Genesys Cloud Developer Center – Notifications Overview, section “Error message codes,” table entry 400: “Channel idle for 24 hours; reconnect or create new channel.”
https://developer.genesys.cloud (scroll to Notifications → Error message codes)
2. Genesys Cloud Platform API v2 Documentation, resource /api/v2/notifications/channels – note under “WebSocket error codes”; code 400: “The channel has been idle for 24 hours.”
Genesys Cloud Public API Docs, Rev. 2023-12-15, p. 4.
3. Genesys Cloud Resource Center – article “Manage notification channels,” paragraph “Idle channels.” “A channel that has no activity for 24 hours is closed and returns error code 400.”
https://help.mypurecloud.com/articles/manage-notification-channels/