Greying out dates on the calendar inside the advance-notice window is separate from refusing bookings for those dates. To have the server also reject them, turn on server-side enforcement.
- Go to HomeRunner Toolkit > Advance Notice Blocking.
- Turn on the Enforce at booking (server-side) switch.
With this switch on, quote and reservation attempts inside the notice window are rejected, using the same boundary the calendar greys out. Where a listing has its own synced notice window, that window applies. Otherwise, the global hours setting is used as the fallback.
A note on the other validation setting. HomeRunner’s separate Validate advance booking hours setting measures from each listing’s check-in time, so its boundary can differ from the calendar boundary by a few hours. When both settings are active at the same time, the settings page shows a Conflicting validation is active notice.