When i complete in playground:
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: NFOWHBOO

When I complete in my developer org:
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: NKPNCSTV

I really don't want to do this a third time.

When i complete in playground:
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: NFOWHBOO

When I complete in my developer org:
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: NKPNCSTV

I really don't want to do this a third time.

I am not able to login to LFO(Lighning for Outlook) in One of the sandbox. I am getting error "Can't access this page. We don't support this browser."   This error is only coming when I am trying to login with Non-System Admin user. With System Admin, I can login to LFO.  Any help on this one would be appreciated.