Ryan, Looks like my URL got cut off, here it is with line breaks. https://oauth2.constantcontact.com/oauth2/oauth/siteowner/authorize? response_type=code& client_id=API_KEY& redirect_uri=https%3A%2F%2Flocalhost%2FPATH_TO_APPLICATION As for other code, there is no other code that really matters. If you replace API_KEY in the URL above with my real API key, you can paste this into a browser and see that: You correctly get taken to an OAUTH authorization page After granting access, you are redirected to the following URL: https://localhost/PATH_TO_APPLICATION?error=redirect_uri_mismatch& error_description=Invalid%20redirect. If things were working, I'd get redirected to: https://localhost/PATH_TO_APPLICATION?code=AUTH_CODE Note that I can change PATH_TO_APPLICATION to a real app location, same result. I can also use a server with a public hostname and not use localhost, same result. Does that help? Andy
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