AR300M - Problems with changing LAN address - SOLVED

I am trying to change the router LAN address. When I do this I get a new login screen that asks for both the password and serial number.
Login is not allowed even when the serial number is entered.
Problem is the same when I use or
Firmware is 2.27

I assume I am missing something simple. Any insight into the reason will be greatly appreciated.

Make sure Javascript is turned on in the browser tab you use to login.

For me, when Javascript was off, it always showed serial number field even when that setting was unchecked, and refused to login. Turning Javascript on made the serial field go away and logins work.

Many thanks for zeroing in on the solution. Noscript is set to trust but I totally forgot that it would cut in when I changed the address to one not listed as trusted.

Again - Thanks for the assistance.

Kind Regards