I know this is a super old issue but I was running into the same problem. The v3 URL is different and is below: https://idfed.constantcontact.com/as/token.oauth2 Take note to the URL above not ending in a forward slash. My issue was that I was using a forward slash: https://idfed.constantcontact.com/as/token.oauth2/ The above URL was giving me a 404 error because of the forward slash. Be wary!
... View more
Hi @VC1977,
This thread is several years old and refers to our v1 API which is deprecated. Are you using the v1 API and encountering this issue, or are you using our v2 or v3 API? If you are using our v1 API I would highly recommend to look in to updating to one of our other versions.
... View more
