In order to use the API service, all calls regardless of the Service, must always contain these three identification pieces:
- API Username (E-mail),
- API Password, and
- Account (list) name.
A very common call exception is that one of these pieces are invalid in some way.
If you are adding SMS contacts via API, your call will also need to include:
- SMS Long Code or Short Code
- SMS Keyword
Need to setup an API user? See this article.