Square form fill payment error - Only one entry is allowed

My square account is connected and live, when I put in credit card payment at the end of the "Membership Application" form I get the following error message.

"Sorry! Only one Entry is allowed"

I have been trying to get it to work for 2 hours, need help

This error is displayed when unique submissions are enabled in the form.  Set unique submissions to "No Check" and it should allow multiple submissions:

Related Guide: How-to-Set-Unique-Submissions-on-a-Form

Can you please configure the payment to be in test/sandbox mode so we could perform a test submission on your actual form? In that way, we could replicate the issue on our end.