Fix email delivery and spam problems

Start with the delivery evidence

• A bounce message usually contains the receiving server's reason and is more useful than a screenshot of the inbox.
• A message in spam was delivered; the issue is filtering or reputation, not basic connectivity.
• No message and no bounce can indicate a queue, forwarding issue, mailbox rule or incorrect recipient address.
• One affected recipient domain points to a different problem than every recipient failing.

Check email authentication

1. Confirm the domain's MX records point to the active mail service.
2. Publish the SPF record supplied by Dprime and keep only one SPF TXT record at the root domain.
3. Publish the DKIM record exactly as shown, including its selector.
4. Add DMARC after SPF and DKIM pass, beginning with a monitoring policy if you are unsure about all legitimate senders.
5. Allow DNS changes to propagate, then send a new test rather than judging an older message.

Check the sender and message

• Scan the device and change the mailbox password if you suspect compromise.
• Avoid bulk sending from a normal mailbox or a website form using forged From addresses.
• Use a transactional provider for high-volume application mail.
• Keep links, attachments and message wording consistent with the sender's identity.