I decided to post this here since it is a similar issue.
I am trying to integrate MailChimp with a homepage form on my website and it doesn’t seem to be working. I followed all the instructions in the article: https://help.webflow.com/article/how-to-integrate-webflow-with-mailchimp
If you look on my site homepage now, you will see two forms. The 3-field form on top is set to absolute position, so it doesn’t look like the form fields are in the form wrapper, so I made a second form (2-field form on the bottom) to test it out. I heard that a possible issue is the fields being in the form wrapper. But it still doesn’t work. I get the “Oops!!” error message.
I tried adding the S in https and switching between actions POST and GET and still nothing.
Here is the preview link to my site: https://preview.webflow.com/preview/gsmarketmedia?preview=d045d4faaabbe45075fe41440fb78f51
Let me know if anyone here can help. Thanks!