Could you provide a topology, explaining how the cameras and the software interconnect.
Are you trying to connect from the same network or some remote location?
In remote access case, is the WAN used wired or mobile?
Do cameras respond to pings from the RUT360?
Could you attach a troubleshoot file to your question? Please, replicate the issue, then access router's WebUI, go to System -> Administration -> Troubleshoot section and download troubleshoot file from there. The logs in the file might provide more insight into the issue.