If you open your Google Mail and the body of all the messages are blank the likely cause is uBlock Origin. To fix the issue, while in GMail, click on the puzzle piece in the Chrome task bar: 
Look for the uBlock Origin icon: 
Click on the icon and the uBlock popup window will open. Click on the uBlock on/off icon to disable for GMail: 
Refresh the page and you should be able to view email again.