Fixing the 'Translation loading triggered too early' Notice in Post SMTP

If you're seeing a PHP notice about _load_textdomain_just_in_time being called incorrectly after updating to WordPress 6.7 or later, you're not alone. This is a common issue reported by users of the Post SMTP plugin. This article explains what causes this notice and provides the most effective solutions to resolve it.

Understanding the Problem

The notice appears because WordPress 6.7 introduced a new translation loading mechanism. The warning is triggered when a plugin attempts to load its text translations (for internationalization) before the init WordPress action hook has fired. The Post SMTP plugin was loading its translations too early in its execution process, which violates the new WordPress standard.

The exact error message is:

Notice: Function _load_textdomain_just_in_time was called incorrectly. Translation loading for the post-smtp domain was triggered too early. This is usually an indicator for some code in the plugin or theme running too early. Translations should be loaded at the init action or later. Please see Debugging in WordPress for more information. (This message was added in version 6.7.0.) in /wp-includes/functions.php on line 6114

While this is a notice and not a fatal error, it can clutter debug logs, and in some cases, if output is buffered, it can lead to "headers already sent" warnings.

Most Common Solutions

1. Update the Plugin

The primary and most straightforward solution is to ensure you are running the latest version of the Post SMTP plugin. The development team has acknowledged this issue and released fixes in subsequent updates. Based on user reports, a fix was implemented and made available in a beta version, which was later included in an official release.

Action: Navigate to your WordPress admin dashboard > Plugins and check for an update for "Post SMTP." Install any available updates.

2. Check for Conflicts with Other Plugins

Some users have reported that this notice appears specifically when using translation management plugins like WPML or when certain other plugins (like WooCommerce) are active. This suggests a potential plugin conflict where another plugin's activity is causing Post SMTP's code to load at the wrong time.

Action: To test for a conflict, temporarily deactivate other plugins one by one (starting with translation plugins) and see if the notice disappears. If it does, you've identified a conflict. You can then reactivate the other plugins and await a compatibility update from either development team.

3. Verify You Are Not Using an Outdated Version

Some support responses in the threads indicate that users were told they were on an older version (e.g., 2.9.14) while a fix was available in a newer release (e.g., 3.0.2). Double-check your currently installed version against the latest version listed on the WordPress Plugin Directory.

4. Temporarily Disable PHP Error Reporting (Not Recommended)

As a last resort, if the notice is purely a cosmetic issue in your logs and does not affect functionality, you could adjust your site's WP_DEBUG settings to suppress notices. However, this is not a fix for the root cause and is generally discouraged as it hides other potentially important messages.

Action: In your wp-config.php file, ensure WP_DEBUG_DISPLAY is set to false to prevent notices from being printed on the screen. Note that they may still be logged if WP_DEBUG_LOG is enabled.

define( 'WP_DEBUG_DISPLAY', false );

Conclusion

The "translation loading triggered too early" notice is a compatibility issue between Post SMTP and WordPress 6.7+. The most effective and recommended solution is to update the Post SMTP plugin to its latest version, as this contains the official fix. If the problem persists after updating, investigate potential conflicts with other plugins on your site.