1. use warnings; use strict;
2. debug => 1
3. protocol and port are not valid args, read the docs

You might do well to read through the example that ships with the module. (snippet follows)

my %args = (ssh_args => []);
$args{debug} = 1 if $opts{v};
push @{ $args{ssh_args} }, compression => 1 if $opts{C};

print "Connecting to $host...\n";
my $sftp = Net::SFTP->new($host, %args);
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