Why does create form using Import Form no longer work?

I want to create a form using an existing form as a base, by importing the existing form using the the import form option, however when I try to do this, I get and error message stating Form not found: Form Id is missing or irregular

I have used this option previously with no problem, why is it now not working?

SD

Hi,

Could you please indicate the URL of the form you are trying to import. I have been able to import a couple (clone) of forms with no issue today.

Regards