I am not sure how this came out last April, but as I am trying to build an OAUTH2 authentication to replace a basic authentication, I don't seem to get past the first request to authorize: https://oauth2.constantcontact.com/oauth2/oauth/{0}/authorize?response_type=code&client_id={1}&redirect_uri={2} after substituting the appropriate client values, I get redirected to a login page, enter name and password and then get a 404. There is no ability to Approve the Access. The redirect_uri is in fact identical to the page I am calling, and also identical to the registered request_uri in the API_KEY. I don't see another reason mentioned for this 404. The next place to look would be...
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