My "search client" feature in A+ is no longer working

I have been using A+ successfully for a couple of years, with thousands of appointments booked.

This week we have noticed that the "search client" search box is not working - it always returns "no appointments have been found" when actually there are. The same problem arises whether we are searching "confirmed", "pending", "removed" lists.

I have tried different browsers - same result.

Has anyone else experienced this? The ability to search is essential... did it break on the latest update?