I am getting this kind of error for the second time after using a new playground and done all the challenge 2 again and about to finish the challenge 3 ( It's a wast of time). I would appreciate if I can get any help to sort this out. Thanks.  Here is the error message: 

" Challenge Not yet complete... here's what's wrong:
There was an unexpected error while verifying this challenge. Usually this is due to some pre-existing configuration or code in the challenge Org. We recommend using a new Developer Edition (DE) to check this challenge. If you're using a new DE and seeing this error, please post to the developer forums and reference error id: DKCKNRLJ

Hello,

I am getting this kind of error for the second time after using a new playground and done all the challenge 2 again and about to finish the challenge 3. I would appreciate if I can get any help tp srt this out. Thanks.  Here is the error message: 

" Challenge Not yet complete... here's what's wrong:
There was an unexpected error while verifying this challenge. Usually this is due to some pre-existing configuration or code in the challenge Org. We recommend using a new Developer Edition (DE) to check this challenge. If you're using a new DE and seeing this error, please post to the developer forums and reference error id: DKCKNRLJ