Emails not sending from my website

Also searched as: email delivery failed · transactional email not working · emails not sending

Updated 9 October 2026

Short answer

Work out where the email stops. Did your site send it at all? Did your email service accept it? Did the recipient's mail server reject it (a bounce), or accept it and put it in spam? The two most common causes: the site isn't set up to send properly (a contact form using the server's built-in mail with no authentication, or wrong SMTP or API settings), and the sending domain lacks SPF and DKIM records, which Gmail's guidelines require.

What's the problem

Password resets, order confirmations or contact form emails don't arrive, arrive in spam, or your email service shows failures.

Why it happens

  • Sending from the web server's own mail function with no authentication, which many inboxes reject or bin.
  • Missing SPF, DKIM or DMARC records for your sending domain.
  • Wrong SMTP or API settings: wrong host, port, username or API key, or a rotated key.
  • The email service blocked or limited your account, for example an unverified domain or too many bounces.
  • The recipient address is wrong or no longer exists.
  • Your hosting provider blocks outgoing mail ports.

How to fix it

  1. Check your site's or app's logs for send errors.
  2. Check your email service's activity log (SendGrid, Mailgun, Postmark, etc.) to see if the message was received, delivered, bounced or blocked.
  3. Use a proper email service instead of the server's built-in mail, connected by API or authenticated SMTP.
  4. Add SPF and DKIM records for your sending domain, as your email service instructs, and a DMARC record.
  5. Verify your domain with your email service.
  6. Test to a few providers (Gmail, Outlook) and check spam folders.

What Preventionlabs checks

One click runs the full report on your domain. For this problem it shows your email authentication: SPF (and its 10-lookup limit), DMARC and DKIM; whether mail to you must arrive encrypted (MTA-STS) and whether you get reports when it does not; your DNS: nameservers, addresses, DNSSEC, and records pointing at services that no longer exist. It can't see your sending provider's delivery logs, so check bounces there.

Run your free report

Your first report is free, no card needed. Then A$50 a month, up to 10 domains. Read-only: it never changes anything.

Sources

  1. Google: Email sender guidelineshelp centerSet up SPF or DKIM email authentication for your sending domains.
  2. Twilio SendGrid: Manage bounced messagesofficial docsWhen the receiving mail server rejects a sent message, a bounce occurs.

Related

SMTP error SMTP errors start with a code: 4xx means temporary (try again later), 5xx means permanent (fix something first). The text after the code says what. Emails bouncing A bounce means the receiving server rejected the email. Read the bounce message: a bad address, a full mailbox, or an authentication or reputation problem. SendGrid error Check SendGrid's activity feed for the message, then the error. Common causes: an unverified sender identity, a wrong or revoked API key, or bounces. Mailgun error Most Mailgun problems come from an unverified domain (a daily limit and "sent via" labels), a wrong API key, or sandbox domain sending rules.
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