To resolve this issue please perform the following steps:
For older Chrome versions;
1. From your browser window click on the Google Chrome Menu button and then click settings.
2. Scroll all the way to the bottom of the page and click on "Show Advanced Settings"
3. Click on the box labeled "Content Settings"
4. Under the Plugins subheading, click on the link "Manage Individual Plugins"
5. Locate the "Chrome PDF Viewer" and make sure that it is enabled. (see below)
For newer Chrome versions;
1. Open your Chrome web browser and select the three vertical dots in the top right corner.
2. Select "Settings" from the drop-down list.
3. Under "Privacy and Security" select "Site Settings".
4. Scroll down and select "Additional content settings".
5. Select "PDF Documents".
6. Enable "Download PDF files instead of automatically opening them in Chrome".