I've found that it is very helpful to include some sort of pseudo-unique "Incident number" in error responses which you also log in the server's log along with

I've found that it is very helpful to include some sort of pseudo-unique "Incident number" in error responses which you also log in the server's log along with any exception/error details. This makes it very easy then to correlate issues reported by users with the actual errors/requests in the log.