Confirmation and success emails are sending with mailChimp service, not in the magento side. So, you need to transfer coupon's code to mailchimp service.
Magento side configuration
Please go to mailchimp cofiguration page:
Stores >> Configuration >> Magemonkey >> Magemonkey >> Mailchimp General Configuration
And add new row to "Customer Fields Mapping".
Enter the following information:
And save the configuration.
MailChimp side configuration
- Go to Mailchimp page and login to your account.
- Go to: Lists >> Click on your list >> Sign Up Forms >> General forms
- Set Option "Forms and response emails" to "final welcome email" and check "Send a final welcome email" option
- Go to: Lists >> Click on your list >> Settings >> List fields and *|MERGE|* tags >> Add a Field
Enter the following information
Field label: Coupon Code
Put this tag in your content: COUPON
Additional fields configuration
Additional fields are working the same as coupon’s code. Use additional fields name for mapping fields instead of np_discount_code.