Every time I try to use a "refresh_token" request I get a 400 error. I am using the latest refresh_token and the URL in the API documentation. I pass the credentials (API Key and API Secret) and do a POST. I am using Java, but no matter what I do I get a 400 error.
There seems to be an issue with the interface, or the code in the sample is wrong and I am missing something.
Any help is appreciated.
After doing more research I found this discussion (https://community.constantcontact.com/t5/Developer-Support-ask-questions/Refresh-token-not-working/m...)
It answered my problem. It was a matter of a refresh_token being generated but, not updating in my central database, and then the 2nd attempt failed.
I'm glad to see that you were able to get the issue resolved. Please let us know if you have any other questions or feedback. We're happy to help.