Instructions for setting up HIS as an authorized sender for your domain (SPF)
If you are hosted a domain outside HIS, but are sending HIS mail services, you will need to add HIS to your domain SPF records so HIS mail servers are listed as an authorized sender for your domain
Here is how to do that
Find out where your domain DNS is hosted.
Login to the DNS manager and locate the TXT records.
Check if there is already an SPF record.
They are TXT DNS record and will look like "v=spf1 some text followed by ~all or -all"
Edit the TXT SPF record and add HIS SPF records (below) to the existing record, before the last part (-all or ~all).
Create an SPF record.
Enter your domain name in the first field. If you send emails from firstname.lastname@example.org, your domain is mydomain.com.
Fill out the fields that appear. The two Emma-related additions you'll make will be to add e2ma.net to the "Any domains that may deliver or relay email for this domain:" field and to say that your edits describe all the hosts that send email from your domain.
Your new SPF record will look something like this:
v=spf1 include:mydomain.com include:his.com -all
You can also use the help of an SPF generator such as SPF Wizard. or ask your domain DNS host to add it for you.