Can anything be done about hotels that show as available when my customer searches but then fail when they try to book?

Yes, this can usually be reduced a great deal, though no system can remove it completely, and it helps to know why it happens. Most hotel and flight suppliers answer a search from a stored copy of their availability so that results come back fast enough for a customer to sit through. The actual room or seat is only held at the moment the booking request is sent. In the gap between those two steps, somebody else may have taken the last room, or the supplier may have changed the price or closed that rate. Your website is simply repeating what the supplier told it, so the failure is happening at the supplier end rather than on your site.

The practical fix is to add a live re-check just before the payment page, where the system goes back to the supplier, confirms the room is still there and confirms the price, and only then lets the customer pay. Most of the larger suppliers support this in their API, but not all of them do, so whether we can switch it on for you depends on which suppliers you are connected to.

It also helps to have more than one source for the same property where your contracts allow it, so that when one supplier refuses, the booking flow can offer the customer a working alternative instead of an error message. Watching which suppliers fail most often is worth the effort too, because the difference between them is often large.

Send us the list of suppliers you are connected to and we can tell you which ones allow a live re-check before payment, and in the meantime keep an eye on your failed booking reports for a few weeks to see whether the trouble sits with one supplier or all of them.