opening PDF is requiring password

When I try to open a PDF that is a saved file on my computer, I receive a message box to enter Password but I haven’t set a password when saving so I can’t satisfy this requirement. Windows 10 PC, LibreOffice Version: (x64)

that is a saved file on my computer

Is it really saved on your computer or is it in fact stored on some network storage device, which requires you to login before you can use it?