(my $id, $first{$name}, $second{$name}) = split /,/;

##</code><code>##

 open ( my $input_1, '<', 'output1.csv' ) or die $!;
  while ( <$input_1> ) {
    chomp;
    my ($name_1, $ip_1) = split /,/;

    my $xml = XML::Twig -> new -> parsefile ( 'example.xml' );
      $xml ->set_pretty_print('indented_a');

    open ( my $input_2, '<', 'output2.csv' ) or die $!;
    while ( <$input_2> ) {
     chomp;
     (my $id, $first{$name}, $second{$name}) = split /,/;
     $xml -> root -> set_att('name', $name_1);
     $xml -> get_xpath('//ipaddress',0) -> set_text($ip_1);
     my $uri="https://hostname:9060/ers/config/networkdevice/$id";
     my $req = HTTP::Request->new('PUT', $uri,
     [Accept=>'application/vnd.com.cisco.ise.network.networkdevice.1.1+xml',
     Content_Type=>'application/vnd.com.cisco.ise.network.networkdevice.1.1+xml; charset=utf-8'], $xml->sprint);

      $req->content($xml->sprint);
      $req->authorization_basic("user", "user");

##</code><code>##

UPDATE need be done for 10.56.7.80
200 OK
400 Bad Request
Use of uninitialized value $id in concatenation (.) or string at My_File line 65, <$_[...]> line 3.
405 Method Not Allowed
Use of uninitialized value $id in concatenation (.) or string at My_File line 65, <$_[...]> line 4.
405 Method Not Allowed
400 Bad Request

##</code><code>##

Line 65: my $uri="https://10.66.1.16:9060/ers/config/networkdevice/$id";