Hello, 
A while ago, I did the Einstein Platform trailheads and signed up for an account for my trailhead playground. 
However, because of this, I am unable to sign up for Einstein Prediction Builder account for the latest trailhead:
https://trailhead.salesforce.com/projects/prediction_builder

It says that my email address has already been used. Therefore, I am not able to complete this trailhead. 

Can someone reset my account so that I can sign up for the latest Einstein Platform account to complete my trailhead?
Thanks!

The Challenge is missing for the above module.  I've refreshed the window several times and logged out of Trailhead, still no Challenge.

I saw another post today, Nov 3rd,  in a different thread with this problem.

For some reason, I am unable to see the 'Challenge' section of this module and hence unable to complete the trail. Any help or pointer?

The Challenge is missing for the above module.  I've refreshed the window several times and logged out of Trailhead, still no Challenge.

I saw another post today, Nov 3rd,  in a different thread with this problem.