I'm trying to add contacts via the API, as talked about in https://help.zoho.com/portal/en/community/topic/how-to-update-leads-custom-field-via-the-api. The result is this:

{code=2006, message=Contact belongs to Do-not-mail registry., version=1.1, uri=/api/v1.1/json/listsubscribe, status=success}

which raises several questions:

1) What is error 2006? It is not listed as a possible result in https://www.zoho.com/campaigns/help/developers/contact-subscribe.html or https://www.zoho.com/campaigns/help/developers/error-codes.html

2) "status=success" should mean that the contact was created. Yet it is nowhere to be found, neither in the list of all contacts, not in the list for which I passed in the listkey. Where can i find it?

3) If "success" does not mean that the contact was created, what do I need change so that it does get created?

The URL I'm using looks like this:

update is something like "{First Name:%s,Last Name:%s,Birth Date:%s,Contact Email:%s}"

Thanks

Ulf