Topic: Question on adjustment mandrill

The customer uses mandrill
It is necessary  coming mail on other domain
It is for this purpose used https://github.com/jonathanargentiero/m … orward-php
Added in inbound routes webhook *@domain.com site/mandrill-inbound-outbound-forward-php
In mandrill-inbound-outbound-forward-php adjusted a key, and added the domain for  *@domain.com
But I receive at sending error Reject Reason: unsigned
On the domain  dkim valid\spf valid
Where to dig?