I'm not able to check my challenge for one of my modules even though I have logged into my trailhead account.



Check Challenge button is greyd out. Need suggestions.

I was able to gain badges for the other modules also I have finished 100 pts questions within this same module.  
1 exercise away from earning a badge and its not allowing me to check challenge. 

Getting 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.DmlException: Insert failed. First exception on row 0; first error: REQUIRED_FIELD_MISSING, Required fields are missing: [Type__c]: [Type__c]

I am currently taking the course Admin Trail Begginer: Getting Started With the Platform, when I proceed to sign up for a DE account I get the following message: "Sorry, we can't enroll you in a Salesforce Developer Edition account because the email address you entered is already in use. To sign up with a different email address, go to https://developer.salesforce.com/form/signup/freetrial.jsp ."

Does this mean I already have a Development Edition Account? If so where would I access it? 
Or should/can I sign up with any email adress fir a DE?