Unable to go to 192.168.1.1 or 192.168

Hello, I have a problem, I tried to open a port with my router D-Link DI-524 then in the address bar I type 192.168.1.1 (I have firefox) it puts me
A timeout

The server at 192.168.1.1 is taking too long to respond.

The browser has waited too long when connecting to the site and stopped to wait for a response.

* The server may be overloaded or temporarily down? Please try again later.

* Other sites are inaccessible? Verify the network connection of your computer.

How little I know if it is installed? x) what I know is that there are three home computer with Internet.