Sometimes the built-in Browser PDF viewer does not display a particular PDF properly.
1) install Adobe Acrobat Reader
Get Adobe Acrobat Reader: http://get.adobe.com/reader/
2) download the PDF first, then view it
You would want to enable Download PDF files instead of automatically opening them in Browser.
Google Chrome Browser
Google Chrome has a built-in PDF viewer.
Windows / Mac OS
Google Chrome has a built-in PDF viewer enabled by default, which opens the file directly in your browser window. To disable the built-in viewer, enter chrome://settings/content in the address bar and scroll down to ‘PDF Documents’. Toggle ON “Download PDF files instead of automatically opening them in Chrome”. Restart Chrome.
Download PDF files OFF

Mozilla Firefox Browser
Mozilla Firefox has a built-in PDF viewer.
Windows
Choose ‘Options’ and go to the ‘Applications’ section. Find ‘Portable Document Format (PDF)’ and click on it to select it. Click on the drop-down arrow in the ‘Action’ column and select ‘Use Adobe Acrobat (in Firefox)’ or ‘Use Adobe Acrobat (default)’ or ‘Save File’ (if you want to download it). Restart Firefox.
Detailed Instructions: https://helpx.adobe.com/acrobat/kb/pdf-browser-plugin-configuration.html
Mac OS
Choose ‘Preferences’ and go to the ‘Applications’ section. Find ‘Portable Document Format (PDF)’ and click on it to select it. Click on the drop-down arrow in the “Action” column and select ‘Use Other’ and select ‘Adobe Acrobat’ or ‘Save File’ (if you want to download it). Restart Firefox.
Detailed Instructions : https://helpx.adobe.com/acrobat/kb/pdf-browser-plugin-configuration.html
Other Solutions
Disable Display PDF in Browser and Fast Web View
Close all browsers. Open Adobe Reader. Choose Edit>Preferences>Internet. In the ‘Web Browser Options’ section, uncheck ‘Display PDF in browser’ and uncheck ‘Allow Fast Web View’. Click ‘OK’ to confirm the change.