The router probably has a local http server for when the internet isn’t connected or configured. It should be written on your router. Something like http://192.168.0.1/ is what I would expect to see.
Also, if there is a problem getting access, like you forgot your password, you can reset everything back to factory settings by pressing a small recessed button on the back or bottom of the router with a pin.
I first tried the link in number 7. I used my password and login that I know were correct when I first set it up a few days ago, it told me my password was wrong, so I tried the default password and user name and that was wrong too, then it completely disconnected me from the internet, no matter what I did, it was no go.
So I disconnected the router and reconnected to my modum and it still would not let me on line. After turning off the modem and back on again several tries, I finally got back on line.
So now I will reconnect my router and reset to default as suggested in number 9 and hope that works. Thanks for the help.