I have a strange problem! So I have a Netgear CG3000 Business Gatgeway and this is actually my second one now because the first one did this same thing.
Everytime I reboot the modem I have access to the 10.1.10.1 for a day or three then poof I get the "server cannot be reached bla bla bla" page. Then if I reboot the modem it is all good again. I have tried to hook a laptop directly to the modem and leave it there and it can access for the same undetermined amount of time before it acts like the modem's internal administration does not exist. A reboot of the computer, assignement of an internal static or DHCP does not matter.
I have had techs come out and replace the modem and it does the same thing. Not like I have to access that very often but I have tried to access it just to test now and its really frustrating waiting till midnight or 1am to reboot the gateway just so I can access the admin pages.