my $hostname=`hostname`;

sub email {

my %mail = ( To      => 'andr@domain.com',
             From    => "$hostname\@domain.com",
             Subject => " $hash_ref->{three} ",
             Message => "$_[0]"
            );

         sendmail(%mail) or die $Mail::Sendmail::error;

}


##</code><code>##

Bad or missing From address: 'DataNode2
@domain.com'