The Zoho CRM field is not supported when the form is embedded on a webpage or when the form's Public URL is directly used to access the form. This is because the Users who are not part of your Zoho Forms org can access the form through the public URL, and fetch data from Zoho CRM.
For the Zoho CRM field to work as intended for your org users,
- Navigate to the Share tab of the form to share the form privately with them. The shared form will be automatically displayed in their form's dashboard.

- The user needs to login to their Zoho Account to access the form, search and populate the data. The User should also have View/Edit permission for the respective module in Zoho CRM so that the fetched data is populated in the form.