Router website default password not working even after a factory reset
So lemme start off by saying that the model above isn't my real router model my real router model is TL-WDR3500 Ver: 1.2.
Around a month ago I decided to upgrade the firmware on the router since it was acting up so I backed up all of my settings on the router(I had a custom DNS setup) and did the upgrade. After the upgrade I was able to log in to the router's website using the default login and once I used the backed up settings the router restarted and didn't let me in back to the website. Since everything was working fine I just didn't think much of it went on with my life. But now I need to log in to the router and I still can't even after many factory resets. I have tried multiple password combinations, but none have worked. I think it might be a problem with the login page since in the console it says(I use firefox):
and sometimes it also says: