SPF lists the servers allowed to send for your domain. DKIM signs each email so it cannot be faked. DMARC tells inboxes what to do when the other two fail.
Since 2024, Google and Yahoo require all three for anyone sending in volume. Without them, cold emails go to spam. Use separate sending domains for outreach so your main domain stays protected.
DNS changes can take up to 48 hours to show. Run the check again after updating records.