Squarespace and OLX embedded forms

We have a donation form embedded on a Squarespace site but it won't render and just says “We're sorry for the inconvenience This form is currently unavailable, but you should be able to use it soon. Please contact the organization if you need immediate assistance.”

Wondering if anyone else is having this issue with Squarespace and if they figured out a way to fix it. It might be a Quirks Mode issue - error in console is that the form is in Limited Quirks Mode, not No Quirks → One or more documents in this page is in Quirks Mode, which will render the affected document(s) with quirks incompatible with the current HTML and CSS specifications.

Is there any way to change this for the form?