Fix Hubspot Non-HubSpot Forms Not Syncing to Mailchimp

If your Hubspot account is not sending contacts from non-HubSpot forms to Mailchimp, you can usually resolve the problem with a few simple checks. This guide walks you through the exact steps to troubleshoot tracking code, form settings, and Mailchimp sync so you do not miss any new contacts.

How non-HubSpot forms work inside Hubspot

Non-HubSpot forms are forms created outside the native forms tool. They live on your website or app but are detected by the tracking code. When the tracking code identifies a compatible form, Hubspot captures the submission details and creates or updates a contact record.

For submissions to appear and sync correctly, the following conditions must be met:

• Your tracking code must be installed and firing.
• The form must be supported by non-HubSpot form detection.
• Mailchimp sync must be active and correctly configured.

Any gap in this flow can prevent contacts from reaching your connected Mailchimp audience.

Step 1 – Confirm the Hubspot tracking code is installed

The tracking code is required for non-HubSpot forms to be detected. Without it, no contact records will be created from those submissions.

How to check your Hubspot tracking code

1. Open your website page where the external form lives.
2. View the page source in your browser.
3. Look for the JavaScript tracking snippet from your account.

If you do not see the snippet, follow the official instructions from Hubspot documentation for non-HubSpot forms and Mailchimp and reinstall the tracking code in your site template or tag manager.

After installing, clear your cache and submit the form again to verify that a new contact appears in your CRM.

Step 2 – Verify Hubspot is detecting the non-HubSpot form

Even with the tracking code, the platform must recognize the form structure to capture submissions. Some custom or embedded forms may not be supported.

Check if the form appears in your non-HubSpot forms tool

1. Log in to your portal.
2. Go to your forms area and open the non-HubSpot forms section.
3. Look for a detected form matching the page where your external form is hosted.

If the form is listed but not creating contacts, click into it and review the mappings for each field. Ensure that essential fields like email are properly mapped to the correct CRM properties.

If the form does not appear at all, try these adjustments:

• Remove complex JavaScript that dynamically replaces the form after page load.
• Avoid forms loaded inside iframes from another domain.
• Use a standard HTML form markup when possible.

After making changes, submit a new test and confirm that Hubspot shows the captured submission in the non-HubSpot forms list.

Step 3 – Make sure the contact is created in Hubspot

Mailchimp cannot receive data if the platform never creates a contact from the submission. Before checking the integration, confirm that each test submission results in a new or updated record.

How to confirm contact creation

1. Submit your non-HubSpot form with a unique email address.
2. In your CRM, open the contacts index and search for that email.
3. Open the contact record and look for the form submission in the activity timeline.

If the contact is missing, the problem is still on the detection side. Revisit tracking code placement, browser extensions that might block scripts, or any script errors on the page.

Only after you consistently see contacts created from submissions should you proceed to investigate Mailchimp sync behavior.

Step 4 – Review the Hubspot and Mailchimp integration

Once contacts are created correctly, the next step is confirming that your integration is turned on, properly configured, and not filtered in a way that excludes your new records.

Check integration status

1. Open your integrations settings and find the Mailchimp connection.
2. Confirm the integration is active and authorized.
3. Verify that the correct Mailchimp account and audience (list) are selected.

If the connection is paused, broken, or pointing to the wrong audience, contacts from non-HubSpot forms will not be added where you expect.

Review sync rules and filters

In many setups, only some contacts are allowed to sync. Inspect your rules to ensure contacts created by non-HubSpot forms meet your criteria.

• Check if only specific lifecycle stages are synced.
• Review any list-based or property-based filters.
• Make sure new contacts from these forms are not missing required properties.

After you adjust the configuration, submit another test form and watch both the contact record and your Mailchimp audience for the new entry.

Step 5 – Confirm field mappings from Hubspot to Mailchimp

Successful sync depends on how fields from your CRM map to Mailchimp merge fields. If critical properties like email are not mapped, contacts can fail to sync or sync with incomplete data.

Validate email and key field mappings

1. In the integration settings, open the field mapping area.
2. Confirm that the email property is correctly mapped to the primary Mailchimp email field.
3. Review first name, last name, and any custom fields captured on your non-HubSpot form.

If you added new properties to store specific form data, be sure each one is linked to a merge field in Mailchimp. Save your settings and retest.

Step 6 – Test Hubspot to Mailchimp sync end-to-end

After you confirm detection, contact creation, and mapping, run a full end-to-end test to ensure everything works together.

Run a full test submission

1. Submit your external form using a brand-new email address.
2. Check the non-HubSpot forms section to confirm the submission is captured.
3. Verify a new contact is created and populated with the expected properties.
4. Wait a few minutes, then check Mailchimp for the new contact in the selected audience.

If the contact appears with the correct data, your configuration is working as expected. If not, return to the previous steps and look for gaps in tracking, detection, or integration rules.

When to contact Hubspot support

If you have walked through these checks and everything appears correct but non-HubSpot form contacts still do not reach Mailchimp, it may be time to escalate.

Before opening a ticket, gather this information:

• The URL of the page containing the non-HubSpot form.
• The email address used in your most recent test submission.
• Screenshots of your integration settings and field mappings.
• Confirmation that the tracking code is installed and active.

Providing these details will help the support team quickly trace the issue and confirm whether it is related to detection limits, integration status, or a configuration detail in your account.

Optimize your setup beyond Hubspot and Mailchimp

Once your forms and sync are stable, you can focus on improving conversion tracking and lead qualification. Consider building segments, using automation, and standardizing properties across tools so that both your CRM and email platform stay aligned.

For advanced configuration, multi-platform strategy, and troubleshooting beyond the basics, you can explore expert Hubspot and marketing automation consulting services from partners such as Consultevo. A structured setup will reduce sync issues and help ensure every non-HubSpot form supports your broader marketing goals.

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