To send emails through our Courier service and ensure they reach recipients, especially those that belong to the Gmail and/or Yahoo domains, you need to make adjustments to your mail DNS records and settings. These changes apply to your SPF, DKIM, and DMARC policies included with your mail server domain, so you comply with Gmail and Yahoo's sending policies. Without these settings in place, Gmail and/or Yahoo are likely to reject any emails sent to recipients within these domains.
Note
Follow these links as they explain what needs to be done. Each of these is from a vendor we use to implement the sending of email through Courier.
Learn how SPF, DKIM, and DMARC work together
Use this link to see your mail domain settings and check whether the SPF, DKIM, and DMARC records have been applied correctly.
Check your mail domain's SPF, DKIM, and DMARC records
Google and Yahoo email policy changes
These resources explain why Google and Yahoo changed their email policies and what they now require from senders: