To authorize Mailchannels to send emails on your behalf you will have to add them to your record. The SPF mechanism used by Mailchannels is shown below.

include:relay.mailchannels.net

For more information on SPF please click on the button below. 

Mailchannels support DKIM signing for your domain, for more information please click on the button below.

Create a free OnDMARC account to test your configuration.