If you receive the error "Document failed upload because there is password security enabled. Please remove the security and try again," then you must remove the password security on the PDF for the system to accept the file upload.
One way to resolve this issue is to use the Print to PDF method to re-save the document. Upload this fixed version of the document and submit your filing.
Another way to resolve the error is to visit the ILovePDF.com website and use the "Unlock PDF" tool to remove the PDF's password security. Upload this fixed version of the document and submit your filing.