Booking.com experienced an outage with their Reservation API.
Started: 2025-06-20, 08:58:03 AM UTC
Finished : 2025-06-20, 09:21:13 AM UTC.
No action is required as Booking.com will resend any reservations that may have been delayed during this period.
If you have any concerns, then go to Settings > Channel Manager > Booking.com > Mapping and click 'Import existing bookings'.