Thank you for pointing that out hippo and NetWallah. I did make use of the synopsis and it gives new error now.

Code:

#!~/perl5/perlbrew/perls/perl-5.28.1/bin/perl
use Modern::Perl;
use WWW::Scraper::ISBN;

my $scraper = WWW::Scraper::ISBN->new();
$scraper->drivers("LOC", "ISBNnu");

my $isbn = "9780134511184";
my $record = $scraper->search($isbn);
if($record->found)
{
    print "Book ".$record->isbn." found by driver ".$record->found_in.
+"\n";
    my $book = $record->book;
    print $book->{'title'};
    print $book->{'author'};
}
else
{
    print $record->error;
}
[download]

Error:

Cannot start LOC query session.
isbn.nu website appears to be unavailable.
[download]

I checked and found that https://www.isbn.nu is working and I can search same ISBN there without any issue. I found the error is coming from ~/perlbrew/perls/perl-5.28.1/lib/site_perl/5.28.1/WWW/Scraper/ISBN/ISBNnu_Driver.pm So I am checking that code to see if I can change something there to make it working.

Here is the code that's generating this error:

sub search {
    my ($self,$isbn) = @_;
    my %data;

    $self->found(0);
    $self->book(undef);

    my $post_url = "https://isbn.nu/".$isbn;
    my $mech = WWW::Mechanize->new();
    $mech->agent_alias( 'Linux Mozilla' );
    $mech->add_header( 'Accept-Encoding' => undef );

    eval { $mech->get( $post_url ) };
    return $self->handler("isbn.nu website appears to be unavailable."
+)
        if($@ || !$mech->success() || !$mech->content());
[download]

Seems one of the three conditions in if are returning true and so the error. I am testing by inserting some prints. Will share here what I find.