thx hippo, your code as posted worked:

my $domain    = $Config->{$sub_hash}->{'domain'};
my $username  = $Config->{$sub_hash}->{'username'};
my $password  = $Config->{$sub_hash}->{'password'};
my $port      = $Config->{$sub_hash}->{'port'};
[download]

but I was curious whether it would still work without the second arrows, and it does:

sub get_tiny {

  use 5.011;
  use warnings;
  use Net::SFTP::Foreign;
  use Config::Tiny;
  use Data::Dumper;

  my $ini_path = qw( /home/bob/Documents/html_template_data/3.values.i
+ni );
  say "ini path is $ini_path";

  my $sub_hash = "my_sftp";
  my $Config   = Config::Tiny->new;
  $Config = Config::Tiny->read( $ini_path, 'utf8' );
  say Dumper $Config;
  # -> is optional between brackets
  my $domain   = $Config->{$sub_hash}{'domain'};
  my $username = $Config->{$sub_hash}{'username'};
  my $password = $Config->{$sub_hash}{'password'};
  my $port     = $Config->{$sub_hash}{'port'};

  #dial up the server

  say "values are $domain $username $password $port";
  my $sftp = Net::SFTP::Foreign->new(
    $domain,
    user     => $username,
    port     => $port,
    password => $password
  ) or die "Can't connect: $!\n";
  return $sftp;
}
[download]

Thx for your comment.