Can't Edit an Interactive Adobe form I created

[LAW2157]

I am trying to edit an interactive Adobe form I created and keep receiving the following error message:

The issue is, I dont have the ability to even select "File" to continue on to save a copy. I don't even have "Save a copy" as an option. I have tried going into the Document Properties and Protection options but nothing has worked. I''m on a Windows computer and I have the most recent version of Adobe Acrobat. 

Someone please assist! Thank you!!

[Bernd Alheit]

Disable the new UI and you can Save a Copy.