Thank you for reaching out to Constant Contact's API Support.
It looks like you are using our v1 API endpoints. That version of the API still works, but is considered deprecated. Is there any particular reason you are trying to use it and not using our current v2 API?
I would suggest moving to the v2 API and using those endpoints. Here is a link to the documentation: http://developer.constantcontact.com/docs/developer-guides/overview-of-api-endpoints.html
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