In this Trailhead challenge : https://trailhead.salesforce.com/en/modules/wave_apps_basics/units/wave_apps_creating_wave_apps 

I am stuck at the step where I have to upload the JSON into the Monitor Data Tasks. While waiting for it to complete .. it fails as in 
this screenshot :


I know in this challenge it is just multiple choice quiz. But in the later Analytics trailhead section, I need to make it succesful in order to complete the step correctly.

Please help