In order to ensure reliable email deliverability through the service, users need to configure APSIS with SPF and DKIM.
SPF
The SPF mechanism that you will have to add to your DNS (if you already have an SPF record) is:
include:_spf.anpdm.com
DKIM
Contact APSIS support for DKIM configuration.
Create a free OnDMARC account to test your configuration.