open pdf says "please fill out the following form" when I attempt to apply redactions, I get an error message. How do I "turn off" the form portion of the document? I assume that is the problem since I have not had this issue with any of the other files

I am attempting to redact a large pdf file.  When I open the file, it has a bar across the top with the message "please fill out the following form".  I can mark redactions, but when I attempt to apply them I get a message saying, "In order to proceed Digital Signatures must be removed and the document must be fully authorized.  Do you want to make these changes and continue?"   I click "ok".  Then I get a message saying, "an internal error occurred."  How do I get around this problem?