I am continuously getting error. I had a new DE. Got the error and again created a new DE. Again in Challenge 2 for App Customization Specialist, I am getting error as below. All are new DEs

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: NUUSMQPR

Hi,

While working on App Customization Specialist module, I am using new DE and passed the first challenge. But with the second challenge, I have started getting error from day before yesterday evening.
Please help.

Error:
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: DECUXHFJ

I'm doing the simple lightning components challenge and have hit this problem in my existing trailhead org and a brand new dev org that I've just created:

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: QVWBQHAG