I'm working on the Redirect_uri_mismatch issue on Clickfunnels.
We're getting redirect_uri_mismatch&error_description=Invalid+redirect when try to log in with oauth2 on production. But on local machine I'm getting redirect loop to that page: https://login.constantcontact.com/login/?goto=https://oauth2.constantcontact.com/oauth2/oauth/login?... - trying to log in and again that page.
The App Redirect URI change doesn't seem to affect something.
Thank you for reaching out to Constant Contact API Developer Support.
I'd like to look into the configuration of your API Key. Please send us an email at email@example.com with your API Key and the redirect URI you are passing through with your OAuth call.
David B.Tier II API Support Engineer