Investigating and Resolving Email Delivery Issues from WordPress Gravity Forms

Emails not Delivered or Marked As Spam

Over the last few months we have observed an increased number of cases where emails generated by Gravity Forms submissions on WordPress websites are either not being delivered or are being marked as spam.

This article explains the root causes of these issues, the corrective actions required, the information we need from customers, and the steps we take as the web developer to implement a reliable solution.

Causes of Email Issues

PHP Mail Function

No SPF / DKIM /DMARC

From Address Mismatch

Hosting Restriction

1. What Causes Email Delivery Issues with Gravity Forms?

Gravity Forms itself is rarely the direct cause of email delivery failures. Instead, the issue almost always lies in how WordPress sends email and how receiving mail servers validate those messages.

1.1 WordPress Default Mail Function (PHP mail())

By default, WordPress sends email using the PHP mail() function. This method:

• Does not authenticate the sending server.
• Does not include proper SMTP-level validation.
• Is frequently blocked or deprioritised by modern email providers.

As a result, emails may:

• Never arrive,
• Be silently dropped, or
• Be delivered to spam or quarantine folders.

1.2 Lack of Email Authentication (SPF, DKIM, DMARC)

Modern mail servers (Microsoft, Google, Yahoo, etc.) require strict authentication. If the sending domain does not have correct DNS records:

• SPF (Sender Policy Framework) may not authorise the web server to send mail.
• DKIM (DomainKeys Identified Mail) may be missing or invalid, meaning messages cannot be cryptographically verified.
• DMARC (Domain-based Message Authentication, Reporting and Conformance) may instruct receiving servers to reject or quarantine unauthenticated mail.

Any one of these misconfigurations can cause delivery failure.

1.3 “From” Address Mismatch

A common misconfiguration in Gravity Forms notifications is using a “From” address such as: noreply@gmail.com or user@domain-that-does-not-match-the-website.com

This creates a mismatch between:

• The sending server,
• The website domain,
• The declared sender address.

Mail servers interpret this as spoofing and will often block the message.

1.4 Hosting Provider Restrictions

Many hosting providers:

• Throttle outgoing email,
• Block PHP mail entirely,
• Require SMTP authentication through approved servers.

Changes at the hosting level can occur without notice and suddenly impact form delivery.

1.5 Increased Spam Filtering Enforcement

Email providers regularly tighten their spam and spoofing detection rules. A setup that “worked for years” may fail abruptly due to new enforcement policies rather than any website change.

Steps To Resolve

Set Up SMTP

Valid DNS Records

Match From Address

Update Form Settings

2. What Needs to Be Done to Resolve the Issue?

The solution is to move away from unauthenticated PHP mail and implement a fully authenticated SMTP-based email delivery process.

2.1 Configure SMTP for WordPress

WordPress should be configured to send mail via a trusted SMTP service, such as:

• The customer’s own mail server (Microsoft 365, Google Workspace, cPanel mail, etc.)
• A transactional email provider (for example, services designed for application-generated email)

This ensures:

• Authentication at send time,
• Improved deliverability,
• Consistent sender reputation.

2.2 Use a Domain-Matching “From” Address

All Gravity Forms notifications must use a “From” address that:

• Exists on the same domain as the website, and
• Is authorised by the domain’s DNS records. Example forms@yourdomain.co.uk

2.3 Correct DNS Authentication Records

The sending domain must have properly configured:

• SPF records authorising the SMTP provider,
• DKIM records supplied by the mail provider,
• DMARC policy aligned with business requirements.

2.4 Update Gravity Forms Notification Settings

Each form notification should be reviewed to ensure:

• Correct “From” and “Reply-To” addresses,
• No use of free email providers (e.g. Gmail, Outlook) as senders,
• Clear separation between sender and recipient fields.

Information Needed From You

Login & Server Info

DNS Access

Preferred Email

Test Recipient

3. Information Required from the Customer

To apply a permanent fix, we require specific information from the customer. Without this, we cannot configure authenticated mail delivery correctly.

3.1 Email Provider Details

Please confirm:

• Who hosts your email (e.g. Microsoft 365, Google Workspace, hosting provider),
• Whether SMTP access is enabled.

3.2 SMTP Credentials (or Approval to Create Them)

One of the following is required:

• SMTP hostname, port, encryption type, username, and password, or
• Approval for us to create a dedicated mailbox (e.g. forms@yourdomain.co.uk) for form sending.

3.3 DNS Access or Delegated Permission

We need either:

• Direct access to DNS management, or
• Confirmation that you will add SPF, DKIM, and DMARC records we provide.

3.4 Preferred Sender Address

Confirmation of:

• The email address that should appear as the sender for form notifications.

3.5 Test Recipient Address

An internal email address where we can send test submissions and verify delivery across inbox, spam, and quarantine folders.

What We Do

Configure SMTP

Update DNS

Send & Verify

Verify & Monitor

4. What We Will Do as the Web Developer

Once the above information is provided, we will handle the full technical implementation and validation process.

4.1 Implement SMTP Configuration in WordPress

• Install and configure a suitable SMTP integration.
• Secure credentials appropriately.
• Disable reliance on PHP mail().

4.2 Update Gravity Forms Notifications

• Align all “From” addresses with the authenticated domain.
• Ensure Reply-To headers are correctly set.
• Remove any configurations that trigger spoofing checks.

4.3 Configure and Validate DNS Records

• Add or update SPF, DKIM, and DMARC records.
• Ensure no conflicts with existing mail services.
• Validate records using standard authentication checks.

4.4 Testing and Verification

• Perform multiple test submissions.
• Verify successful delivery to major providers.
• Confirm messages are not flagged as spam.

4.5 Ongoing Guidance

• Advise on best practices for future forms.
• Document the configuration for reference.
• Provide recommendations if email provider policies change.

Investigating and Resolving Email Delivery Issues from WordPress Gravity Forms Summary

Email delivery issues from Gravity Forms are almost always the result of modern email authentication requirements clashing with legacy WordPress mail behaviour. The resolution is not a patch or plugin tweak alone, but a proper SMTP-based configuration supported by correct DNS authentication.

With the required information from the customer, we can implement a secure, compliant, and reliable email delivery setup that aligns with current industry standards and significantly reduces the risk of future delivery failures.

Reliable & Secure Email Delivery