I replied with the link that is at the bottom of every single post you make when you are previewing that explains READMORE tags. You should go back and edit your post with READMORE tags.

You failed to mention that the page made extensive use of JavaScript. Notice the "Apply " button - onClick="toApply(document.Wanblock) The WWW::Mechanize FAQ would have told you that it is a client that doesn't understand JavaScript. When you try it in a regular browser, does it work with JavaScript turned off? I suspect not. The following code would work if JavaScript wasn't involved:

#!/usr/bin/perl
use strict;
use warnings;
use WWW::Mechanize;

my $url= 'http://192.168.0.1/WanService.html';
my $mech = WWW::Mechanize->new( autocheck => 1 );
$mech->credentials(
    '192.168.0.1:80',
    'FVS318',
    'admin' => 'secret'
);
$mech->get( $url );
$mech->tick('EnBt3', '1');
$mech->click_button( value => "Apply " );
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