WRT 1900AC Port Forwarding Error 2118

Everytime I try to use the factory's firmware "Security" Tab I get:

Error: 2118

http://linksys.com/jnap/firewall/GetPortRangeForwardingRules : {} -- Status: 200 OK Date: Fri, 09 Jan 2015 03:27:38 GMT Server: lighttpd/1.4.34 Connection: close Content-Length: 3982 Content-Type: application/json; charset=utf-8

It just started recently and I can't save any settings in the whole security tab pages. Port fowarding also stopped working.

1.1.8.164461 Firmware installed

Any help would be much appreciated... Thanks.