Error while updating to v3

Regular Participant

While trying to update to version 3 of the api, I am getting an error.


When I send this URL to generate access token

I receive this:





Hello SpencerF23,


Thank you for reaching out to Constant Contact API Developer Support. My team is here to assist outside software developers with questions about building into Constant Contact's API.


The reason you encountered this error is that your authorization request URL did not include the state parameter, which is required for the initial authorization request. The state parameter is an arbitrary string value used to uniquely identify a user’s session. For more information on this parameter, you can review the Request Parameters section under Step 1 of the Authorization Code Flow documentation I’m linking below.


V3 API Authorization Code Flow:


Please have a look and let us know if you have any other questions!



John B.
API Support Specialist
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