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Fixing Mailchimp Integration Issues with Events Manager Multi-Booking Mode

21 threads Sep 9, 2025 Plugin → Mc4wp: mailchimp for wordpress

Content

Many users of the 'MC4WP: Mailchimp for WordPress' plugin encounter a specific problem when integrating with the Events Manager plugin, particularly when using its Multi-Booking Mode (MBM). Submissions fail silently, and no data appears in Mailchimp or the plugin's log. This guide explains why this happens and provides the most common solutions to get your integration working.

Understanding the Problem

Based on community reports, the 'MC4WP: Mailchimp for WordPress' plugin's Events Manager integration does not function in Multi-Booking Mode. The integration is designed to work with Events Manager's Single Booking Mode (SBM), where a booking is made for a single event at a time. In MBM, where users can book multiple events in a single transaction, the standard integration hook is not triggered at the correct point in the process, causing the subscription data to be lost.

Common Symptoms

  • No new subscribers are added to your Mailchimp list after an MBM booking.
  • The "Log" section in MC4WP > Other shows no entries related to the booking.
  • If you switch to a hidden field, you might see a [ERROR] Form > Submitted with errors: spam log entry.
  • The integration works correctly when Events Manager is switched to Single Booking Mode.

How to Troubleshoot and Resolve the Issue

1. Verify the Integration is Set Up Correctly

First, ensure your basic integration is configured properly, as an issue here could compound the MBM problem.

  1. Navigate to MC4WP > Integrations in your WordPress admin dashboard.
  2. Click on the Events Manager integration.
  3. Ensure the status is set to Enabled and that you have selected the correct Mailchimp list.
  4. Check the Double opt-in setting. If enabled, subscribers must confirm their email address before being added to your list, which can cause a delay.

2. Enable Debug Logging

To see what the plugin is doing, enable detailed logging. This can help confirm if the plugin is even attempting to process the form submission.

  1. Go to MC4WP > Other.
  2. Under the "Logging" section, select the Log everything option.
  3. Save the settings.
  4. Make a test booking in Multi-Booking Mode.
  5. Return to the Log and check for any new entries. Even an error message is a valuable clue.

3. Use a Custom Integration (Recommended Workaround)

The most common and reliable workaround for MBM is to bypass the built-in Events Manager integration and use a Custom integration instead. This involves manually placing a checkbox on your final checkout or registrant information form.

  1. Go to MC4WP > Integrations and click on the Custom integration.
  2. Enable it and select your desired Mailchimp list and settings.
  3. The plugin will provide a code snippet. It will look something like this: 
    <label>
    <input type="checkbox" name="mc4wp-subscribe" value="1" />
    Subscribe to our newsletter.
</label>
  4. You must add this HTML code to your Events Manager registrant form template. The specific file to edit depends on your theme, but you often need to copy the forms/booking-form.php file from the plugin directory to your theme (e.g., your-theme/events-manager/forms/booking-form.php) and edit it there.
  5. Critical: Ensure the checkbox is placed on the final form where the user enters their name and email, not on the initial event booking page.

4. Check for Field Mapping Errors

If you start getting log entries after implementing the custom checkbox but see API errors, you likely have a field mapping issue. A common error is: Mailchimp API Error: Bad Request. Invalid Resource. Your merge fields were invalid. - FNAME : Inserisci un valore - LNAME : Inserisci un valore

This means Mailchimp is expecting a value for the FNAME and LNAME fields, but it's receiving nothing. To fix this:

  1. Ensure your Events Manager form is collecting the user's first and last name.
  2. The field names in your form must be correctly mapped. Often, using mc4wp-FNAME and mc4wp-LNAME as the field names will automatically map them to the correct Mailchimp fields.

Conclusion

The lack of native support for Events Manager's Multi-Booking Mode is a known limitation. While the 'MC4WP: Mailchimp for WordPress' team has acknowledged this issue in community forums, a built-in fix is not currently available. The most effective solution is to implement a Custom integration by manually placing a subscription checkbox on your final booking form. By carefully following the steps above, particularly the custom integration workaround, you can successfully capture subscriber data even in Multi-Booking Mode.

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