How to embed forms into Squarespace?

Squarespace says the forms are not embeddable. What am I doing wrong? How can I embed the form in the Squarespace website?

Please try to follow the steps provided here: https://www.jotform.com/help/37-adding-form-to-squarespace

If you've already done this, please share with us a screenshot of the error message that is being shown so we can better understand what's happening.