You need to configure SPF for a domain used in the envelope-from, usually, the email and this address shows as the reuturn-path. If it coincides with email@example.com to publish SPF it is necessary for him, but ucast IP address (or addresses) of the server
company.com. TXT "v=spf1 ip4:188.8.131.52 ~all"
where 184.108.40.206 is the server address. You can use and design
company.com. TXT "v=spf1 a:mail.server.com ~all"
but it is preferable to use IP addresses.