Understand how the plugin experience looks for the customer

If you’re experiencing issues with Postmark’s WordPress plugin, the best way to troubleshoot is by recreating the setup in your own test environment. This guide will walk you through testing the plugin using WordPress Playground or WordPress Local, and how to review logs and settings to identify what’s causing messages not to send.

1. Set up a WordPress test site

The easiest way to create a temporary WordPress site for testing is to use WordPress Playground, a browser-based sandbox environment.

Go to WordPress Playground.
(Note: the URL includes ?plugin=postmark-approved-wordpress-plugin, which automatically installs the Postmark plugin.)
Wait a few seconds for your Playground instance to load.
Click Admin to open the WordPress admin dashboard.

Alternative: Use WordPress Local

If you prefer testing on your computer, you can use Local by Flywheel.

Download and install Local.
Create a new site and click Admin to access your WordPress dashboard.
Continue following the same steps below to install and configure the Postmark plugin.

2. Install and configure the Postmark plugin

Once you’re in your WordPress dashboard:

Navigate to Plugins → Installed Plugins.
Confirm that ActiveCampaign Postmark is installed.
If not, you can install it manually by searching for “Postmark” under Plugins → Add New.

Then go to Settings → ActiveCampaign Postmark and check the following:

✅ Enabled — allows emails to be sent through Postmark.
✅ Enable Logs — records delivery logs to help with troubleshooting.

If logs aren’t enabled, please ask your customer to turn them on before reproducing the issue so they can share screenshots of their logs.

3. Identify why messages aren’t being sent

Most delivery problems can be diagnosed by reading the plugin’s log messages.

For example:

If no logs appear at all, this usually indicates a conflict with another plugin that also modifies or overrides the wp_mail() function.
Since the Postmark plugin replaces WordPress’s default mail handler, it cannot coexist with another plugin doing the same. For this reason, it’s also not possible to send only some of your WordPress emails through Postmark — it’s all or nothing.

4. Send a test message

The Postmark for WordPress plugin includes a Send test email feature to confirm that your connection to Postmark is working correctly.
Use this to verify your credentials and sending settings before testing integrations with other plugins.

5. Test sending from other WordPress plugins

Let’s look at a few common ways customers send emails from WordPress.

Sending via Ninja Forms

Go to Plugins → Add New and search for Ninja Forms.
Click Install Now and then Activate.
In the sidebar, click Ninja Forms to view existing forms. You’ll see a default form you can use for testing.
Click the gear icon on the default form, then open the Emails & Actions tab.
Select the gear icon next to Admin Email.
By default, the “From” address is your WordPress admin email (found under Settings → General).
Update it to use an address that’s verified in Postmark.

Example:
- From Address: verified@yourdomain.com
- To Address: your personal or admin email address
Click Done, then Publish your form.
View your live site (hover over your site name → Visit site) and submit the contact form.
Return to Settings → ActiveCampaign Postmark → Logs to confirm that the email was triggered and sent successfully.

📚 For more details, see Ninja Forms’ official documentation.

Sending via WooCommerce

To test sending from WooCommerce:

Go to Plugins → Add New and search for WooCommerce.
Click Install Now and then Activate.
From your dashboard, go to WooCommerce → Orders → Add order.
Under Order Actions, select Resend new order notification and click Create.
The message will be sent to the recipient address listed under WooCommerce → Settings → Emails.
The From address will be whatever is configured in the Postmark plugin settings.

6. Troubleshoot common problems

Issue	Possible Cause	Solution
No emails or logs appear	Another plugin is overriding `wp_mail()`	Disable other email-related plugins temporarily and retest
“From” address not allowed	The address isn’t verified in Postmark	Add and confirm the address in your Postmark account
Emails delayed or not received	Plugin not enabled or incorrect credentials	Check Enabled setting and verify your Postmark API token
Logs missing	Logging not enabled	Turn on Enable Logs in plugin settings

Summary

To recap:

Create a test WordPress environment (Playground or Local).
Install and enable the Postmark plugin.
Turn on logging for troubleshooting.
Review logs for clear error messages.
Test sending using the built-in test email, Ninja Forms, or WooCommerce.
Ensure your “From” address is verified and no conflicting plugins are active.

If you still can’t send messages after following these steps, please contact Postmark Support with:

A screenshot of your Postmark plugin settings
A screenshot or copy of the log error message
The version of WordPress you’re using

Our team will be happy to help you dig deeper.