To authorize Votervoice to send emails on your behalf you will have to include it in your SPF record. The SPF record mechanism used for Votervoice is shown below.
Votervoice support DKIM signing for your custom domain.
For more information on how to set up SPF & DKIM for Votervoice please see click on the button below.
Create a free OnDMARC account to test your configuration.