The password can only be changed inside the router inferface. If its not working, most likly you either forgot the password, or your not typing it in correctly. Could be a issue where it didn't save the password correctly, but that is unlikly. Eitherway, your onlu recourse (other then the previous suggestions) is a factory reset.
Jun 24, 2020 Can't login to DLINK Router. Nov 25, 2011 D-Link Malaysia
My Account Philippines - D-Link
Your router must be connected to a modem in order to provide the local network with an Internet connection. Acquire an Ethernet cable. Take one end of the cable and plug it into the Internet (or WAN) port on the rear of your router.The port may be blue or grey. Hardware Version: A1 : Firmware Version : 1.00NA: Login. Log in to the router
Dlink DIR-842 Default Router Login and Password
Your router must be connected to a modem in order to provide the local network with an Internet connection. Acquire an Ethernet cable. Take one end of the cable and plug it into the Internet (or WAN) port on the rear of your router.The port may be blue or grey. Hardware Version: A1 : Firmware Version : 1.00NA: Login. Log in to the router If that doesn't work, and your D-Link router is connected to a computer, the configured default gateway is the access IP address for the router. Learn how to find the default gateway IP address , then look for the IP address in your computer's network settings.