I found out what I was doing wrong above. I was signing headers that didn't exist: The below code added to the sender policy fixed things, while making it so I am not signing parts of the header that I shouldn't be: my $policyfn = sub { my $dkim = shift; $headers = join ':', grep { $_ !~ /^(message-id|date|return-path|bounces-to)$/i } (split ':', $dkim->headers); $dkim->add_signature( new Mail::DKIM::Signature( Algorithm => "rsa-sha1", Method => "relaxed", Headers => $headers, Domain => "bearpile.com", Selector => "mail", )); return; }; also, I need to add a From=>"$from" in the following code: $msg = MIME::Lite->new( To =>"$to", From =>"$from", Subject =>"testing DKIM via SES", Type =>'multipart/alternative', ); I hope this information helps others as I know how frustrating this is, especially when there isn't many examples on the web of altering which headers to use in a sender policy.