Hi, 
I'm about to finish this trail Get Started with Salesforce DX  Continuous Integration Using Salesforce DX Wire It All Together  but ended up with this error in Travis. See screenshot below: 


Any comments or suggestion would be a big help. I'm trying to learn the concepts of the SFDX and CI. 
Thanks in advance!

Trying to complete "Community Rollout Strategy" and Create Sharing Rules Unit. Everytime I click on "Check Challenge", I get this error: 

Challenge Not yet complete... here's what's wrong: 
There was an unexpected error in your org which is preventing this assessment check from completing: System.QueryException: List has no rows for assignment to SObject

Any advice? Or do I have to start a new DE org?