How to modify Document Properties - dialog and properties

[OBXJack39]

Trying to Optimize and reduce the size of an existing pdf file and am unable to proceed because of the pop-up message ''You do not have sufficient permissions to perform this task.  Please change the security settings from the Document Properties dialog and entry."

The Document Properties file/folder can not be found and would appreciate input from the community.  I possess administative authorities.

[Peru Bob]

Moved from the Premiere Pro forum to the Acrobat forum.

[try67]

What do you see under File - Properties - Security (from within Acrobat)?