The addresses work. Why is the email going to spam?

A verification result says little about where a message will land. A working mailbox can receive your email in the inbox, put it in spam, or reject it because of how you sent it.

If your addresses check out, look at the actual delivery reports before running the same list again.

Start with authentication. Follow your sending platform's instructions for SPF, DKIM and DMARC, then check a delivered message to see whether they pass. A DNS record being present isn't enough. DMARC also checks whether an authenticated domain aligns with the domain in the visible From address.

Look for a pattern. Are failures concentrated at one provider? Did they start after a platform change or a jump in sending volume? A cluster of authentication or policy errors needs a different response from a cluster of nonexistent mailboxes.

Check what recipients expected. Someone who requested a receipt hasn't necessarily asked for a newsletter. Make the sender recognisable, keep the message relevant, and make unsubscribing easy. Look at complaints and replies alongside campaign statistics.

Review changes to the message itself. Broken links, misleading subjects or a compromised destination can cause problems even when the address is correct.

Gmail's sender guidelines cover its requirements directly. Use the provider's current guidance rather than a universal “safe” percentage from a blog.

Finally, be specific about the problem. A message in Gmail's Promotions tab has reached the inbox. A message rejected by the receiving server hasn't. Those need different investigations.