At around noon on Friday we became aware of some issues with booking.com's booking retrieval system, where some reservations were not sent to us, and fallback emails/faxes contained no information. Consequently, booking.com put a reservation hold on all properties while they worked on the issue.
Any bookings that weren't automatically imported into your account will need to be manually added while booking.com work on a solution.
Booking.com have confirmed that the problem was corrected on the same day, and offered the following information:
Booking.com was experiencing significant performance issues with reservation services on the Friday 25th May.
Start time: 12:40 25th May CEST (8:40pm AET) (11:40am British Summertime)
End time: 20:20 25th May CEST (4:20am +1 AET) (7:20pm British Summertime)
This was a broad outage that also affected our ability to send fallback emails.
A hold was placed on reservations shortly after the outage began so the reservations could be sent once services were restored.
When services resumed some reservations will have been delivered directly to partners by email fallback. If a partner has received a blank reservation email they may have a reservation affected prior to the hold. They can retrieve the reservation by visiting their Booking.com extranet and looking for reservations made around the same timestamp as the email.