https://ttlc.intuit.com/community/tax-topics/help/e-file-rejection-an-xml-document-that-represents-a-binary-attachment-must-have-a-valid-reference/00/1042625
All PDF file names must be unique and can't have any spacial characters or spaces (the period is fine). The article above can help resolve your issue.
e.g. MorganStanley.pdf