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?
Re: error 400 - Unknown or invalid client_id
1 reply
Webinar
Is your small business or nonprofit losing time and engagement to outdated or confusing social media advice? April 23, 2026 2:00 pm ET
Popular Posts:
The world's largest virtual email marketing conference. November 12-13th.
