[BUG] Products Not Syncing to Mailchimp - Sync Status Remains at Zero

[maxor389]

The Mailchimp for WooCommerce plugin sync is stuck at zero for contacts, promo codes, orders, and products (0, 0, 0, 0). Existing products (approximately 1600) are not syncing to Mailchimp. New products created via the WooCommerce admin interface do not sync. For context, the sync was not bringing new products to the mailchimp website/app, hence we cleared all the data from the app/website and tried to sync again.

Interesting observation: 


• I Created a product via the WC-API (POST to /wp-json/wc/v3/products endpoint) and it syncd. Did it again for another product and it also syncd. However any product created by the admin UI, does not sync.

Steps to reproduce the behavior:

1. Go to the WordPress admin dashboard of the WooCommerce store.
2. Create a new product using the WooCommerce admin interface.
3. Wait for the Mailchimp sync process to initiate.
4. Check Mailchimp to verify if the new product has synced, or view the settings page of MC.
5. Observe that the product has not synced, and the sync status remains at 0 contacts, 0 promo codes, 0 orders, and 0 products.

Expected behavior All existing products should sync to Mailchimp during the initial sync process. New products created via the WooCommerce admin interface should automatically sync to Mailchimp.

• Staging URL: https://tccfast.staging.tempurl.host/
• Production URL: the-coin-chest.com
• Plugin version: 4.4
• WooCommerce version: 9.3.2
• WordPress version: 6.6.2
• PHP version: 8.2.23
• Theme: Twenty Twenty-Four (in staging environment)

Additional Information

• The issue began about a week ago when new products were not syncing to Mailchimp.
• Disconnecting and reconnecting the store from Mailchimp did not resolve the issue.
• The problem persists in both production and staging environments.
• In the staging environment, all plugins except WooCommerce and Mailchimp were deactivated and deleted, but the issue remained.
• I have a staging environment available for further testing and am willing to provide additional information if needed.

[maxor389]

UPDATE:

After numerous attempts to resolve the syncing issue - including trying different troubleshooting methods and reaching out to my hosting provider—nothing seemed to work. I even downgraded WooCommerce to version 9.2.2, but the problem persisted.

The breakthrough came when I decided to downgrade the Mailchimp for WooCommerce plugin from version 4.4 to 4.1. Upon setting up a new sync with version 4.1, all products and data began syncing correctly, and the issue was no longer present.

To confirm this, I deactivated and deleted version 4.1 of the Mailchimp plugin, then re-upgraded to version 4.4. Unfortunately, the syncing issue returned immediately. This clearly indicates that the problem is specific to version 4.4 of the Mailchimp for WooCommerce plugin.

Conclusion: Downgrading to Mailchimp for WooCommerce version 4.1 resolves the syncing issue, while version 4.4 causes the problem to persist. It seems there may be a bug introduced in the newer version of the plugin.

I hope this information assists in diagnosing and fixing the issue in future releases.

[khungate]

Hi @maxor389, thanks so much for reaching out about your issue. We'll take things from here and do some testing on our end and report back as soon as we can.

[khungate]

Hi @maxor389, we’ve issued a patch for this in our upcoming release. If you’d like to give it a try now, you can, but please ensure you back up your site beforehand, as it hasn’t gone through formal QA yet: https://github.com/mailchimp/mc-woocommerce/tree/4.4.1. We hope to push this out very soon, thanks for reporting 👍