In the case where your file contains lines but you get 0 read line after uploading your file:
This might be due to the line endings of your file. For Mac Users, line endings could be "Mac OS 9".
This type of line endings is not recognized by our system. You can change it, using Sublime Text application on macOS:
Once you change the line endings, save your file and try to upload it again. Therefore, you should see the difference: