Re: error 400 - Unknown or invalid client_id

0 Votes

I don't think this is an issue with Gravity Forms after reaching out to their developers. I am running into the same issue and I get locked out when getting redirected to Constant Contact to connect. Any update or ideas on how to fix this issue?

0 Votes

Hello FirstNameL10197,


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.


Based on reports from other Gravity Forms users in the community, Gravity Forms has released an update since this post addressing our new authentication flow which should now allow you to successfully connect the plugin with your Constant Contact account. Below I’m including a link to Gravity Forms’ manual update instructions. 


Gravity Forms Manual Update Instructions:


Gravity Forms Plugin Constant Contact Change Log:


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



John B.
API Support Specialist
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