Why are my emails bouncing back?

Email bounce is not always avoidable during an email campaign

Anyone who has ever sent out a large amount of emails for newsletters or promotional purposes will know about bounced emails. Whenever you are dealing with a huge mailing list with thousands of email addresses, it is inevitable that you will receive a percentage of emails being bounced back whenever you perform large scale email sending.

 

Common reasons for getting bounced emails

  1. Your email content contains the following:
    • Spam keywords like Buy now, Free trial, Viagra, You have been selected & Take action now
    • Misleading URLs that tries to mimic real site URLs like http://youtube.com.[actual domain].com
    • Phishing content where the email body pretends to be coming from a legitimate organization like a bank to steal user’s login info
    • Generic content like Dear customer instead of addressing the recipient by name
    • Using deceptive From names, reply-to email addresses or subject line
    • No unsubscribe link
  2. Keeps sending email even after recipient unsubscribed
    • Once a user has unsubscribed from your mailing list, it is not wise to keep sending them any emails.
  3. Blacklisted IP or domain
    • If your email server reputation is bad because you have been flagged as a spammer, your IP or email domain may be blacklisted via spam lists like Spamhaus or Spamcop
  4. Too many emails sent to the same ISP in a short period
    • Some ISPs employ greylisting where your email will be rejected for a period of time, after which you can safely send email again
  5. Your mail server does not have DKIM or SPF
    • SPF (Sender Policy Framework) is a DNS entry which is like a whitelist of server IPs that are allowed to send email for your domain
    • DKIM (DomainKeys Identified Mail) is a verification method (using a DNS entry with the DKIM key) to confirm that the email content is trustworthy & has not been tampered with since being sent out from the mail server
  6. Invalid message id in the email header
    • Your email was sent using programs that did not generate a unique message id for that particular email
  7. No PTR record for your email domain DNS entry
    • The PTR record is for mapping an IP address to your domain so is a form of verification that the email did come from your domain hence the lack of a PTR record will leave the origin of your email in doubt

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