This is normally a problem when the recorder is not networked correctly on the local network.
The best way to troubleshoot this is to open the recorders network settings > Enable DHCP and save.
Next exit and then reopen the main menu and recheck to see if the device is online
Please follow our tutorial on how to add a device to the EZCloud.
The second problem could be that the recorder has no network connectivity at all. To trouble shoot this first check to make sure that you have link lights on the recorder and on the networking device. Then check your cat5 cable and try a new one if necessary.