Port Forwarding Error - Not working

I have a Netgear D6300AC wireless router, I had setup a port forwarding for RDS 3389 to one of my PCs on my network, however when I try to delete that entry from port forwarding list and try to setup a new rule for another device using same port 3389 it doesn't let me do that, I keep getting

 

"The specified port(s) are being used by other configurations. Please check your configurations of USB Readyshare, Remote Management, Port Forwarding, Port Triggering, UPnP Port Mapping table, RIP, and Internet connection type. "

 

I tried factory resetting the router few times, also upgraded its firmware to the latest version (Firmware Version 1.0.0.102 (All Regions Except NA and Germany)), however I have no resolution to the problem.

 

Any help will be highly appreciated.

 

Thanks