Quick answer
If customer confirmation emails are not arriving, check whether your application actually triggered the email, whether your sending provider accepted and delivered it, whether your domain has valid SPF, DKIM and DMARC records, whether the message landed in spam, whether the address bounced or was suppressed and whether the template content triggers filters. Use provider delivery logs to trace a specific message.
Key takeaways
- Confirm the application triggered the email before blaming delivery.
- SPF, DKIM and DMARC alignment strongly affect inbox placement.
- Bounces and suppression lists silently block future emails.
- Monitor delivery events instead of relying on customer complaints.
Who this guide is for
Ecommerce, SaaS and service businesses whose customers report missing order, booking, password reset or sign-up emails.
Trace one specific message
Start with a concrete case: the customer’s email address, the time and the type of email. Check application logs to confirm the event happened and an email job was created. Then check the sending provider’s logs for that address and time. This shows whether the problem is before sending, at the provider or after delivery. Avoid sending repeated test emails to real customers while investigating; use approved test inboxes at different providers such as Gmail and Outlook.
Check the application side
Emails may never be sent because a background job failed, a queue is stuck, a template has an error, a configuration value points to the wrong environment or an exception occurs after the order is saved. Look for errors around the email step and confirm the job worker is running. If the email is sent synchronously during checkout, a failure might be swallowed silently. Moving sending to a monitored queue with retries makes failures visible and recoverable.
Check provider acceptance and delivery
Email services such as Amazon SES, SendGrid, Postmark, Mailgun or Resend show whether a message was accepted, delivered, deferred, bounced or marked as spam by the recipient. Acceptance by the provider does not guarantee inbox delivery. Look for bounce reasons such as invalid address or mailbox full, and check whether the address is on the provider’s suppression list because of an earlier bounce or complaint, which blocks all future sends silently.
Verify domain authentication
Mailbox providers check whether your domain authorizes the sending service. SPF lists permitted senders, DKIM signs messages cryptographically and DMARC tells receivers how to treat messages that fail and requires alignment with your visible From domain. Missing or misconfigured records are a common reason transactional emails land in spam. Major mailbox providers have tightened requirements for bulk senders, so check current guidance from Google and Yahoo and verify records with your DNS provider.
Review content and sending patterns
Spam filters consider content, links and sender reputation. Use a recognizable From name and address, avoid link shorteners and misleading subject lines, include plain-text versions and keep transactional emails separate from marketing campaigns, ideally on different subdomains or streams. Sudden volume spikes from a new domain can harm reputation. A reply-to address that people can actually use also improves trust signals.
Handle the customer’s side
Some issues are local: a typo in the address, corporate filters quarantining external mail, full mailboxes or aggressive spam settings. Validate email format at entry and consider confirmation of the address for accounts. Show confirmation details on screen as well, so customers have the information even if email fails. Let customers resend confirmations from their account or order page.
Monitor delivery continuously
Use provider webhooks to record delivery, bounce and complaint events against each message in your system. Alert when bounce or failure rates rise. Periodically send test emails to seed inboxes at major providers. A review typically covers application triggers, queue reliability, provider logs, DNS authentication, content and monitoring, and ends with a written list of fixes and their verification.
Scope checklist
- Did the application create an email job for the missing message?
- What does the provider log show for that address?
- Are SPF, DKIM and DMARC valid and aligned?
- Is the address on a suppression list?
- Are delivery events monitored?
Frequently asked questions
Why are my transactional emails going to spam?
Common causes include missing or misaligned SPF, DKIM and DMARC, poor sender reputation, mixing marketing and transactional mail, and spam-like content or links.
What is DMARC and do I need it?
DMARC is a DNS policy that tells receivers how to handle mail failing SPF or DKIM checks and requires alignment with your From domain. Major mailbox providers increasingly expect it.
How can I check if an email was delivered?
Check your sending provider’s logs or activity feed for the recipient and time, and record delivery events from provider webhooks in your system.
Sources and implementation references
- Google: email sender guidelines
Gmail’s requirements for authentication and sending practices.
- DMARC.org overview
Explanation of DMARC policy and alignment.
Prepared with AI assistance as an engineering decision guide. Examples are illustrative unless explicitly labelled as an internal implementation. No independent expert review or customer outcome is claimed.
Need help investigating this issue?
Describe what is failing and which platform you use. Do not submit passwords, API keys, or confidential customer data. Scope, access, dependencies and commercial terms are agreed before delivery. Do not submit passwords, API keys or confidential records.
