Here is the list of causes and solutions to resolve this issue:
- PDF file is not in a virtual directory
- Missing Adobe Reader plug-in
- Older version of browser application
- Older web server version that handles PDF (or other files types) incorrectly
- PDF file get damaged
Try following soluttions to fix this issue:
- Disable view in browser feature
- Check if any problem with web server
- Download PDF to local drive
- Install Adobe Acrobat viewer