How to set up SMTP for WordPress contact forms

Why do WordPress contact forms need SMTP?

WordPress contact forms need SMTP because, out of the box, WordPress sends email through your web server's own mail function, and receiving mail servers have little reason to trust it. Contact Form 7, WPForms, Gravity Forms and the rest all hand their emails to WordPress's wp_mail() function, so they share the same weakness.

Two things go wrong. Some hosts limit or switch off the server's mail function, so the email is never sent at all. More often it is sent, but Gmail or Outlook can't tell that your server is allowed to send for your domain, and the enquiry lands in spam or disappears. Our post on why WordPress form emails go to spam explains that second problem in more detail.

An SMTP plugin deals with both. It replaces the server's mail function, so every email your site sends, password resets and shop orders included, goes out through a mail service that signs in, is trusted by other providers and reports errors you can read.

Which SMTP plugin should you use?

For most small sites, FluentSMTP or WP Mail SMTP will do the job, and the choice comes down to which features you want without paying. The three popular plugins are all free to install from the WordPress plugin directory, and all three can send a test email. At the time of writing, their free versions compared like this [CHECK]:

WP Mail SMTP is the best known, and its set-up wizard is easy to follow. Its directory listing is "WP Mail SMTP by WPForms", so it comes from the team behind the WPForms form plugin. FluentSMTP is the one to choose if you want an email log and a backup connection for nothing. If you use Gravity Forms, its makers sell their own Gravity SMTP plugin, and have add-ons for Mailgun, Postmark and SendGrid that send form notifications only.

Install one SMTP plugin, not two. They all take over the same part of WordPress, and two of them can get in each other's way.

Which sending service should you connect it to?

If your business email is already on Google Workspace or Microsoft 365, start there: you already pay for it, and your domain is set up for it. Otherwise, a transactional email service such as Brevo or Mailgun is built for this job, and a contact form sends so few emails that a free plan usually covers it. These were the allowances at the time of writing [CHECK]:

If you use Microsoft 365, note that Microsoft is retiring Basic authentication (a plain username and password) for SMTP in Exchange Online, and at the time of writing plans to turn it off by default for existing tenants at the end of December 2026 [CHECK]. A plugin that connects with Microsoft's own sign-in avoids the problem, and FluentSMTP includes one free.

Avoid sending through a personal Gmail or Outlook.com account. The email then comes from that account rather than your domain, which brings back the problem you set out to fix.

How to set up SMTP in WordPress

Setting up SMTP takes six short steps once you've chosen a plugin and a service, and the plugin's wizard walks you through most of them. The steps below suit a sending service such as Brevo or Mailgun. With Google Workspace or Microsoft 365, you skip the first two and sign in with that account instead of pasting a key.

1. 1

   Create the sending account

   Sign up with the sending service and add your domain, such as acmeplumbing.co.uk. It gives you DNS records to add and an SMTP password or API key.

2. 2

   Add the DNS records

   Add the SPF and DKIM records it gives you wherever your domain's DNS is managed, then wait until the service shows the domain as verified.

3. 3

   Install one SMTP plugin

   In WordPress, go to Plugins → Add New Plugin, search for WP Mail SMTP, FluentSMTP or Post SMTP, then install and activate it.

4. 4

   Connect the service

   Run the plugin's set-up wizard, choose your service as the mailer and paste the key, or sign in with Google or Microsoft. Use Other SMTP only when your service has no mailer of its own.

5. 5

   Set the From address

   Enter a From address on your own domain, such as [email protected], and your business name as the From name.

6. 6

   Send a test email

   Use the plugin's test page to send a message to an inbox you check, and fix any error it reports before you go further.

Do the DNS step even if the test email arrives without it. Without SPF and DKIM, the service is sending on your behalf with nothing to prove it may, and some of your enquiries may still end up in spam.

What should the From and Reply-To addresses be?

The From address should be on your own domain, and the visitor's address should go in Reply-To. The email is then honestly from your website, and pressing Reply still writes to the person who filled in the form.

Many forms are set up the other way round, with the visitor's address in From. Your server then sends a message claiming to come from someone's Gmail or Yahoo account, which is what forged email looks like. Gravity Forms' documentation warns against it and names Yahoo, AOL and Gmail among the providers with policies that catch it. WPForms shows "The current From Email does not match your website domain name" under the field when the domain is wrong.

Check the setting in two places. The SMTP plugin has a From address, and most can force it on every email the site sends. The form plugin has its own, in the form's notification or mail settings (the Mail tab in Contact Form 7). Set the form's Reply-To to its email field, using the tag the form plugin gives that field.

How do you check SMTP is working?

Send a real enquiry through your own form and check it lands in the inbox rather than spam. The plugin's test email proves the connection works; only a real submission proves the form's own settings are right too.

1. Fill in the form with an email address that isn't the one it sends to, and look in both the inbox and the spam folder.

2. Open the plugin's email log, if it has one, and confirm the email shows as sent.

3. Check the sending service's own log, which shows whether the receiving server accepted it.

4. Open the email, view its headers ("Show original" in Gmail) and look for a pass for SPF and DKIM.

If SPF or DKIM fail, the DNS records aren't right yet. Our guide to SPF, DKIM and DMARC explains what each record does and how to check them. For Contact Form 7's own settings, work through the Contact Form 7 not sending email checklist.

Is SMTP enough on its own?

SMTP makes form emails far more reliable, but every enquiry still depends on one email reaching one inbox. A full mailbox, a changed password on the sending account or a new filter can still lose a message without anyone noticing.

Two safeguards cost nothing. Keep a copy of every submission on the site: Gravity Forms stores entries, Contact Form 7 needs the Flamingo add-on, and WPForms Lite doesn't keep entries. And switch on your SMTP plugin's failure alerts if it has them, so a broken connection doesn't go unnoticed for weeks.

Formcrier is one more option. It sends each submission to your phone on WhatsApp, a text, Telegram, Slack or Microsoft Teams within seconds, without going through your site's email, using its WordPress plugin or a script tag. It's free for 10 alerts a month.