Email Delivery Troubleshooting and SMTP Plugins

WordPress sites at Pressable send emails using our own email provider which is usually reliable. However, sites that send a high volume of emails or that experience emails not being received by all intended recipients should consider using an SMTP (Simple Mail Transfer Protocol) plugin to increase control over and deliverability of emails.

Basic Email Delivery Troubleshooting

If emails sent from your site are not being delivered as expected, you can begin the troubleshooting process with some or all of the following:

  • Ensure that all emails sent by your site, including emails sent by plugins, are sent from email addresses that match the primary domain name of your site. For example, if your primary domain name is, you should ensure that all emails come from something like instead of
  • If the emails that aren’t being delivered come from a specific plugin, check the documentation for that plugin or reach out to the plugin developer directly for insight. For example, WooCommerce has a guide that covers several email settings.
  • Check whether the deliverability issues are restricted to only one email address or one specific email provider. Many universities have strict email filtering, for example. 
  • Ensure that your users/customers have checked their spam folders. Occasionally emails sent from a WordPress site can be mislabeled as spam. 
  • Install an email logging plugin to gather more information to aid in continued troubleshooting. Some examples of logging plugins include Email Log and WP Mail Logging.
  • Consider using an SMTP plugin (see following section) to improve email deliverability, particularly if your site generates a high volume of email traffic or is having consistent issues with email bouncing/being flagged as spam.
  • Contact Pressable Support. Although configuring DNS records related to email deliverability or setting up an SMTP plugin do fall outside the scope of support we are always happy to provide as much insight and guidance as possible.

How SMTP Plugins Work

By default, WordPress uses a method called PHP mail() to send emails, but sometimes that can cause problems like emails not getting through or being marked as spam.

An SMTP plugin can solve this problem. It replaces the default mail() function with a dedicated SMTP service, such as Gmail, SendGrid, or Mailgun (among others). This makes sure your emails are sent properly and increases the chances of them actually reaching the recipients’ inboxes.

If you already have an email provider for your domain, you can almost certainly make use of an SMTP plugin to route your site’s email through that provider.

If you do not already have an email service provider for your domain, which is a requirement to use an SMTP plugin, some options to consider include the following.

Advantages of using an SMTP Plugin

  1. Reliable Email Delivery: By default, WordPress uses the PHP mail() function to send emails. However, this method can be unreliable, leading to issues like emails not being delivered or ending up in spam folders. An SMTP plugin ensures that your emails are sent through a dedicated SMTP server, which significantly improves deliverability rates and reduces the chances of your emails being marked as spam.
  2. Enhanced Email Authentication: SMTP plugins allow you to authenticate your emails properly, which adds credibility and trustworthiness to your outgoing messages. When you connect your WordPress site to an SMTP service, such as Gmail, SendGrid, or Mailgun, it ensures that your emails are properly authenticated with DKIM (DomainKeys Identified Mail) and SPF (Sender Policy Framework), increasing the chances of successful email delivery.
  3. Avoidance of Email Delivery Issues: Many SMTP plugins provide advanced features that help you troubleshoot and resolve email delivery issues. They offer detailed logs and notifications, allowing you to track the status of sent emails and identify any potential problems. With this information, you can resolve issues promptly, ensuring that your important messages reach the intended recipients without delay.
  4. Better Reputation and Deliverability: Sending emails directly from your WordPress server can sometimes lead to a poor sender reputation, as shared hosting environments might have a history of spamming. By utilizing an SMTP plugin, you leverage the reputation and infrastructure of a trusted SMTP service provider. This improves your email sender reputation, leading to better overall deliverability rates.
  5. Flexibility and Compatibility: SMTP plugins offer compatibility with various SMTP service providers, giving you the flexibility to choose the one that best suits your needs. Whether it’s Gmail, Outlook, Sendinblue, or another SMTP service, these plugins enable seamless integration, ensuring smooth email communication from your WordPress site.

Overall, using an SMTP plugin for your WordPress site is a proactive step to overcome email delivery challenges, increase reliability, and maintain a professional image. It improves email authentication, reduces the likelihood of emails going to spam, and provides valuable tools for monitoring and resolving any delivery issues that may arise.

From simple to advanced, these three plugins are a good starting point for adding SMTP email delivery to your site.

  1. Easy WP SMTP: This plugin is perfect for those seeking a straightforward solution without compromising on functionality. It’s simple to configure SMTP settings using your favorite providers like Gmail, Yahoo, or Outlook.
  2. WP Mail SMTP by WPForms: Perhaps the most popular SMTP plugin, WP Mail SMTP provides its core features for free but access to setup wizards for some email services does require a paid upgrade. Plus, WP Mail SMTP provides detailed logs and notifications, so you have access to troubleshooting info if needed.
  3. Post SMTP Mailer/Email Log: Post SMTP Mailer/Email Log not only ensures reliable email delivery but also includes an email logging system. Keep track of sent and received emails, and dive into detailed logs to diagnose and troubleshoot any potential issues. Additionally, this plugin provides debugging tools and the ability to retry failed email deliveries.