Could you please clarify if you don't see anything connected to the device when going to the overview of the device or you don't see anything when going to RMS connect and scanning the device for connected devices?
If scanning give no results, could you try to add the device manually by providing the IP address and port used?
It would be great if you could replicate the issue, then access router's WebUI, go to SYSTEM > ADMINISTRATION > TROUBLESHOOT section, download troubleshoot file from there and send it to me.
Logs in this file will help to answer what cause this issue.
Thank you in advance.