How to troubleshoot web form emails that are not delivering?
Michael Ko
Co-founder & CEO, Suped
Published 12 May 2025
Updated 17 Aug 2025
6 min read
It can be frustrating when your web forms are collecting submissions, but the notification emails aren't reaching your inbox. This is a surprisingly common problem that can stem from various points in the email delivery chain, from the website's server to the recipient's mail server.
Finding the root cause requires a systematic approach, as it's rarely a simple fix. We'll walk through the key areas to investigate to troubleshoot and resolve issues with web form emails not delivering, ensuring your important communications land where they should.
Initial checks and verifying the send process
Before diving into complex deliverability issues, the first step is always to confirm that the web form script is actually sending emails and that they aren't getting caught by a local spam filter. Many times, the issue isn't with delivery to the final inbox, but rather that the email never even left the sending server, or it's sitting in a junk folder.
Always check your spam or junk folder first. It might seem obvious, but many legitimate form submissions are mistakenly routed there. If you find them, mark them as 'not spam' to help train your email client. Beyond that, verify the email addresses configured in your form settings for any typos or incorrect formatting. A simple mistake here can prevent any emails from being sent at all.
Test with a simple PHP script
To confirm whether your web server can send email at all, try using a very basic PHP mail script. This bypasses any form plugin complexities and directly tests the server's mail function. If this test email doesn't arrive, you know the problem is with the server's email sending capabilities, not necessarily your form itself.
Basic PHP mail testphp
<?php
$to = "your_email@example.com";
$subject = "Test email from web form";
$message = "This is a test email sent from your website's PHP script.";
$headers = "From: webmaster@yourdomain.com";
if (mail($to, $subject, $message, $headers)) {
echo "Test email sent successfully!";
} else {
echo "Test email sending failed.";
}
?>
Authentication and DNS records
Once you've confirmed your server is attempting to send emails, the next critical area to examine is your domain's email authentication records. Without proper Sender Policy Framework (SPF), DomainKeys Identified Mail (DKIM), and Domain-based Message Authentication, Reporting, and Conformance (DMARC) configurations, mail servers are likely to flag your form emails as spam or reject them outright.
Incorrect or missing SPF records are a common cause of web form email delivery issues. Your SPF record tells receiving mail servers which IP addresses are authorized to send email on behalf of your domain. If your web server's IP isn't included, emails can fail SPF authentication, leading to bounces or spam filtering. You can troubleshoot common SPF and DNS issues for intermittent failures.
DKIM adds a digital signature to your emails, allowing recipients to verify that the email hasn't been tampered with and truly originated from your domain. DMARC builds upon SPF and DKIM, providing instructions to receiving servers on how to handle emails that fail authentication. For a more comprehensive understanding, explore a simple guide to DMARC, SPF, and DKIM. Utilizing DMARC monitoring can provide invaluable insights into your email authentication status.
Common DNS record issues
Missing records: No SPF, DKIM, or DMARC record published for your sending domain.
Incorrect values: Typos or outdated IP addresses in your SPF record.
Multiple SPF records: Only one SPF TXT record is allowed per domain.
DMARC policy: A 'p=reject' or 'p=quarantine' policy can cause emails to be blocked if authentication fails.
Server and hosting environment
The way your website's server sends email can significantly impact deliverability. Many shared hosting environments default to using PHP's mail() function, which often sends emails without proper authentication, making them susceptible to being flagged as spam.
Using a dedicated SMTP (Simple Mail Transfer Protocol) service is almost always a better approach. SMTP provides a more reliable and secure way to send emails, allowing for proper authentication. Your hosting provider might also have specific email sending limits or policies that could be affecting your form's emails. Sometimes, server-side firewalls or misconfigured ports can block outbound email traffic, preventing messages from ever leaving your server.
It's worth reviewing your hosting provider's documentation or contacting their support to understand their email sending policies and ensure no server-side blocks are in place. For those using Microsoft 365 or Google Workspace, official troubleshooting guides for email delivery issues are available. For Microsoft domains, specific deliverability issues may arise.
PHP mail() function
Relies on the server's default mail sending configurations, which are often basic and lack proper authentication mechanisms. This can lead to emails being easily filtered as spam.
Dedicated SMTP service
Connects to a professional email service (e.g., Google Workspace, Outlook, or a third-party SMTP provider) that handles sending with proper authentication (SPF, DKIM). This dramatically improves deliverability.
Reputation and recipient-side filtering
Even with correct configurations, your sender reputation and the recipient's mail server filters play a huge role in whether your web form emails reach the inbox or are shunted to spam. Email providers like Gmail and Outlook are increasingly strict, using a combination of factors to determine inbox placement.
Your sending IP or domain might be listed on a blocklist (or blacklist). These lists compile IP addresses and domains associated with sending spam. If you're listed, mail servers will likely reject your emails. Regular blocklist monitoring is crucial. Find out what happens when your domain is on an email blacklist and how to address it. Furthermore, sending to spam traps can severely damage your sender reputation.
Content of your web form emails can also trigger spam filters. Avoid using overly promotional language, excessive capitalization, or suspicious links. Ensure your form emails are concise and provide clear information. If you're struggling with transactional emails going to spam, consider best practices for inbox placement. For Gmail troubleshooting, be aware that they are tightening their sending requirements, which might lead to your emails going to spam.
Best practices for content
Clear subject lines: Avoid spammy phrases, use specific and professional subjects.
Plain text option: Ensure a plain text version exists for HTML emails.
Personalization: Use details from the form submission to make the email relevant.
Views from the trenches
Best practices
Always use a reputable SMTP service for sending web form emails instead of the server's native PHP mail function for better deliverability and authentication.
Implement and correctly configure SPF, DKIM, and DMARC records for your sending domain, regularly checking their validity.
Monitor your domain and IP addresses for any blocklist (blacklist) listings and address them promptly to avoid deliverability issues.
Regularly test your web forms with different recipient email addresses (including Gmail, Outlook, etc.) to catch issues early.
Ensure your web form email content is clear, concise, and avoids spam trigger words or excessive formatting.
Common pitfalls
Relying solely on PHP mail() without proper SMTP configuration, leading to poor sender reputation and spam filtering.
Incorrectly configured or missing SPF, DKIM, or DMARC records, causing authentication failures and rejections.
Not checking spam or junk folders on the recipient's side, assuming emails are not being sent at all.
Ignoring server-side logs, which can provide crucial insights into whether emails are being attempted or rejected locally.
Allowing web forms to be used for spam, which can quickly lead to your sending domain being blocklisted.
Expert tips
Use your hosting provider's logs or cPanel's email delivery report to verify if the server attempted to send the email and the outcome.
Consider setting up DMARC reports to get visibility into authentication failures and identify potential issues with your web form email sending sources.
If using a CMS like WordPress, install an SMTP plugin to easily configure sending via a professional email service.
Always use an authenticated 'From' address that matches your domain, rather than a generic or spoofed address, to improve trust.
Regularly audit your form's
Marketer view
Marketer from Email Geeks says to begin troubleshooting by confirming that the script is actually generating mail and attempting to send it, as this distinguishes a script issue from a deliverability problem.
2023-12-29 - Email Geeks
Marketer view
Marketer from Email Geeks says that access to SMTP logs is crucial for diagnosing issues, as they reveal whether emails are being accepted or rejected by the mail server, which helps determine if it's a deliverability issue.
2023-12-30 - Email Geeks
Key takeaways for reliable web form email delivery
Troubleshooting web form emails that aren't delivering can feel like a complex puzzle, but by breaking it down into logical steps, you can effectively pinpoint and resolve most issues. The key is to verify each stage of the email's journey, starting from the moment it's submitted on your website.
From confirming your script is actually sending, to ensuring your DNS records are flawlessly configured for authentication, and monitoring your sender reputation, a proactive approach to email deliverability ensures your web forms function as intended. Regular checks and attention to detail will help maintain consistent and reliable email delivery from your website.
Microsoft 365 or 
Google Workspace, official troubleshooting guides for email delivery issues are available. For Microsoft domains, specific deliverability issues may arise.
Gmail and 
Outlook are increasingly strict, using a combination of factors to determine inbox placement.
