Unable to add handler. Ajax error

Problem/Motivation

When I try to add the handler, nothing happens. Therefore, I cannot get this module to work. Using Drupal 8.9.13 with Webform 6.0.2

Steps to reproduce

1) Go to the email/handlers tab
2) Click the "add handler" button. A popup appears.
3) Click the "add handler" button for Commerce Webform Order Handler
4) The popup box closes and nothing else is showing. No options to are shown to configure the handler.

It appears to be an Ajax error as the browser console shows:

AjaxError:
An AJAX HTTP error occurred.
HTTP Result Code: 200
Debugging information follows.
Path: /admin/structure/webform/manage/donation_form/handlers/add/commerce_webform_order
StatusText: OK
ResponseText:

I am able to add other handlers. Can anyone help with this?

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes