@HardwareMan 

Hi,

Test if you can get past the login if you type a simpler password. Use only numbers and english letters, no symbols or special Portuguese characters.

Once you've managed to login you can later change the password to something else via the "Advanced" - "System Tools" - "Administration" menu. I guess you will have to try what works and what doesn't.

  @woozle I'm trying to set the password when starting the router for the first time on the home screen, because I reset my router.

  @HardwareMan 

I know, so I suggested you test if it works with a simpler password.

If you need me to be more specific.

At the login screen shown in your screenshot type 123456 in the upper password field, then type 123456 in the lower password field and then click on the button "Vamos Comecar". Do you still get the message "Falha de Login"?