I have received an error code 303 in Book step

During the last step of the booking flow, you may receive the error code 303 together with a type description.

This type of error is not very common, but it can happen.

Response example:

 <type>303</type> <description>Booking not confirmed</description>

The description is quite clear and informs that due to X reason the booking could not be confirmed.

You may receive status UN in this reservation. When the
ResStatus field appears as UN and an application error is also returned with the type = 303 we cannot ensure the booking has not been confirmed in the Seller's system.

If you receive this error and the status is UN, we strongly recommend you to first launch the DescriptiveInfo/ Booking method to check the real status of the booking. If you still receive the status UN in the response, you MUST contact the Seller directly to confirm the actual status of the booking.