Dgate send

If I was to use dgate send commands to send my images from one Server to a central server what will happen to the images being sent from the one location if the central server goes down or losses connection for some reason. Will those images fail and just not send or will dgate keep trying until it can reach that central server. I have 50+ location that will be sending to a central location and can not have all those locations images fail and not be sent to the central location.