E11000 duplicate key error index: freecodecamp.people.$name_1 dup key: { : "Dorian Gray" }

Hi, I’m stuck on this challenges - ( Introduction to the MongoDB and Mongoose Challenges )

8 - Perform Classic Updates by Running Find, Edit, then Save
9 - Not PassedPerform New Updates on a Document Using model.findOneAndUpdate()

I get these messages on the console:

// running tests
E11000 duplicate key error index: freecodecamp.people.$name_1 dup key: { : “Poldo” }
// tests completed
// running tests
E11000 duplicate key error index: freecodecamp.people.$name_1 dup key: { : “Dorian Gray” }
// tests completed

Thank you in advance.

Hi, me again.
Finally, I could overcome these challenges, but to do it I had to delete some docs in mLab.
Maybe these challenges are a little buggy.
I hope this solution could be helpful for others students.