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Troubleshooting Common OptinMonster Plugin Errors in WordPress

29 threads Sep 9, 2025 Plugin → Popup builder & popup maker for wordpress – optinmonster email marketing and lead generation

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Users of the 'Popup Builder & Popup Maker for WordPress – OptinMonster Email Marketing and Lead Generation' plugin sometimes encounter errors that can prevent their websites or campaigns from functioning correctly. This guide compiles the most common issues and their solutions, based on community reports.

1. PHP Version Compatibility Errors

Problem: Fatal PHP errors, such as Parse error: syntax error, unexpected '.' or Uncaught Error: Call to a member function admin_page_url() on null, often appear after a plugin update.

Why it happens: These errors typically occur when the WordPress site is running an outdated version of PHP that is no longer compatible with the plugin's code.

Solution: Upgrade your site's PHP version to 7.4 or higher. This is a critical security and performance step. You can usually change your PHP version from your hosting provider's control panel (e.g., cPanel). If you cannot upgrade PHP immediately, you may need to manually reinstall a compatible version of the plugin, but upgrading PHP is the recommended long-term fix.

2. Live Site Inspector & Embed Code Detection Issues

Problem: The Live Site Inspector fails, showing errors like "We weren’t able to find the embed code on this page" or "The Test on Page widget did not load correctly", even though the plugin is installed.

Why it happens: This is frequently caused by a browser extension, firewall, or caching plugin blocking the OptinMonster JavaScript. Occasionally, the embed code needs to be re-triggered in WordPress.

Solution:

  • First, test using your browser's incognito or private mode to rule out extensions.
  • Clear all caching on your site (server, plugin, and browser cache).
  • Navigate to OptinMonster > Campaigns in your WordPress admin. Change a campaign's status from Draft to Published, then back to Draft. This can often re-initialize the embed code.

3. API Connection and cURL Errors

Problem: The plugin cannot connect to the OptinMonster API, resulting in a cURL error 28 (connection timeout) or a 400 error.

Why it happens: Strict server security policies may be blocking the outbound connection to api.omwpapi.com on port 80.

Solution: If you are unable to adjust your server's firewall rules to allow the connection, the recommended workaround is to manually add the embed code to your theme. You can copy the code snippet from your OptinMonster account and paste it directly into your theme's footer.php file just before the closing </body> tag.

4. JavaScript Conflicts and Admin Panel Issues

Problem: The OptinMonster dashboard doesn't load, or you see a warning that "JavaScript Didn’t Load" in your WordPress admin.

Why it happens: A conflict with another plugin or your theme is preventing JavaScript from executing properly.

Solution: Perform a standard conflict test:

  1. Deactivate all other plugins except OptinMonster.
  2. Switch to a default WordPress theme like Twenty Twenty-One.
  3. Check if the issue is resolved. If it is, reactivate your plugins and theme one by one to identify the culprit.

5. Campaign Output and Display Problems

Problem: Campaigns that were working suddenly disappear or their design settings are reset after an update.

Why it happens: Updates can sometimes change how campaign rules and settings are stored or applied.

Solution: After a plugin update, review your campaign settings in the OptinMonster app and re-save them. For campaigns not displaying, double-check the display rules and page targeting settings within the campaign editor. Adding a specific page slug to the targeting rules can often resolve the issue.

If these steps do not resolve your issue, the problem may be more specific to your site's configuration. For further assistance, you can consult the official 'Popup Builder & Popup Maker for WordPress – OptinMonster Email Marketing and Lead Generation' documentation.

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