The SPF record, or "Sender Policy Framework", is a special DNS (Text) record that informs receiving mail servers of who is allowed to send e-mail on your behalf. While optional, it is strongly advised to set this up.
If you already have an SPF record or are setting one up, it is necessary to indicate that the storefront is authorized to send mail on your behalf. If this is not done, password reset emails and order confirmations may be rejected causing unnecessary confusion or frustration with your customers. To allow this, please add "include:amazonses.com" to your SPF record.
For Example, a typical record using Outlook 365 will look like this:
"v=spf1 include:spf.protection.outlook.com include:amazonses.com -all".