What could be causing the error in the console when trying to integrate Mailchimp with Webflow and the form is not submitting?

A Webflow form not submitting when integrated with Mailchimp typically points to issues with the form action URL, input field names, or CORS restrictions.

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1. Incorrect Mailchimp Form Action URL

• Go to your Mailchimp audience, click Signup forms > Embedded forms, and look for the form action URL.
• It should look like: https://<dc>.list-manage.com/subscribe/post?u=XXXXXXX&id=XXXXXXX.
• Paste that entire URL in the Webflow form's action field under the Form Settings panel.
• Ensure the URL uses https, not http.

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2. Mismatched Input Field Names

• Mailchimp expects exact name attributes (e.g., EMAIL, FNAME, LNAME).
• In Webflow, select each input field and set the name exactly as required by Mailchimp.
• For example:
• Email input field name should be EMAIL.
• First Name: FNAME.
• Last Name: LNAME (if used).
• Do not use custom field names, or Mailchimp will ignore the data.

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3. CORS/JavaScript Block by Mailchimp

• Mailchimp forms are not designed to work with Webflow’s AJAX submit system.
• Disable AJAX submission in Webflow to allow a traditional form post:
• Select the form.
• Go to the Settings panel.
• Scroll to Form Settings, and check "Disable Webflow form".
• This makes the form submit via a standard POST request directly to Mailchimp.

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4. Missing or Invalid Hidden Inputs

• Mailchimp sometimes requires hidden inputs (especially for GDPR-related features).
• If your pasted embed code includes hidden fields like bxxxxxxxxxxxx = "", you must include them.
• Without these, Mailchimp may silently reject the form or fail to process it correctly.

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5. Console Errors Indicate Network/CORS Problems

• If the browser console shows CORS-related errors or network request failures:
• It means the POST request is being blocked by the browser since the request is cross-origin.
• This confirms why AJAX must be disabled—Webflow’s async submission doesn't work with Mailchimp due to Mailchimp's CORS policies.

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Summary

To successfully connect Mailchimp with Webflow:

• Use the correct Mailchimp form action URL.
• Match input field names to Mailchimp's requirements.
• Disable AJAX submission in Webflow.
• Include necessary hidden fields if provided by Mailchimp.
• Monitor the console for CORS or network errors to confirm if Mailchimp is rejecting the submission.

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These steps usually resolve 90% of Mailchimp–Webflow integration issues.