Submit form not working

When someone tries to submit a new email to subscribe to our newsletter, it gives them the “Oops something went wrong” error.

I have my MC API key input and connected properly in the settings.
When I submit an email address that has already signed up to our newsletter, it reads that correctly, and gives the proper response, and I have renewed my mailchimp lists, and that ran successfully too. Not sure what’s up.

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