use strict; 
use LWP::UserAgent;

my $url = "https://server.xyz.de/about.php";
my $pw='123456';
my $us='abcdef';

my $ua = LWP::UserAgent->new;

   
   $ua->timeout(10);
   $ua->requests_redirectable(undef); # Redirects ausschalten!
   
   $ua->credentials("server.xyz.de:443", "POP3", $us, $pw);
      
   $ua->proxy( https  => 'http://my.proxy:8080');
   
   $ua->add_handler("request_send",  sub { shift->dump; return });
   $ua->add_handler("response_done", sub { shift->dump; return });

my $response = $ua->post($url);
   
   
   if ($response->is_success) {
     
     print $response->status_line;
     print $response->decoded_content;  # or whatever
  }
   else {
     die $response->status_line;
   }