No Longer Able to Enter Forms in Acrobat Reader DC

I downloaded and was using Adobe Acrobat Reader DC for some days up to yesterday to fill out forms. Today, I am not being allowed to enter new information or edit information previously entered. I am getting the following pop-up: "This document enabled extended features in Adobe Acrobat Reader. The document has been changed since it was created and use of extended features is no longer available." Please contact the author of original version of this document."