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.
Most issues with connecting Contact Form 7 to Constant Contact arise due to one of two things:
The redirect URI is not copied exactly from the Contact Form 7 plugin in WordPress into the Redirect URI field for your API key in Constant Contact at https://app.constantcontact.com/pages/dma/portal/ .
Otherwise, a new Secret may need to be generated for your key and brought over from Constant Contact to WordPress.
Contact Form 7 - Constant Contact integration instructions
Please note that Contact Form 7 is a 3rd party product and not built or supported by Constant Contact, so we are limited in the support we can provide, but will try to answer any questions to the best of our ability as they pertain to Constant Contact’s API endpoints and functionality. Constant Contact makes these endpoints available for 3rd party developers to create integrations with our system.
Please have a look and let us know if you have any other questions!
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