The email delivery issues to email addresses with the domain @guest.booking.com are now resolved. These were caused by a temporary performance issue at Booking.com.
If you sent any emails to @guest.booking.com addresses during the outage period, please make sure to resend them. If you have any related questions, feel free to contact us at email@example.com.
Email outage started: 2022-01-03. Email outage ended: 2022-01-13.