Sometimes when looking through your pull zone logs, you will see requests appear with a status code 499. While this might look worrying, 499 errors are natural and will sometimes happen over connections such as mobile networks that can suffer from a load interruption etc. or even when for example an ad blocker will block a file request.
These are not codes that are not actually returned to the user, 499 is just an internal server code that means that the client has closed the connection before processing the request and receiving the reply.
