Can you confirm what happens if our system (using the api) tries to add a contact to a new list in Constant Contact but that contact already exists and his email address is marked unsubscribed?
1) Does this result in a non-fatal error?
2) This apparently will not add the contact to the new list. Please confirm.
When you attempt to add a contact who is unsubscribed, the outcome depends on the API call you are using. Here are the details:
Bulk Import Contacts API:
Individual Contact APIs:
If you have any questions for me, please let me know!