I had my 2nd phone screen but failed.

It a dp problem (Finding longest path in a 2D matrix type of problem - Leetcode Medium type of question).
Complete the problems in 35mins and had some time for a quick chat. ( maybe i said something wrong?)

I don't understand why I failed since I started the questions with a brute force solution and eventually worked towards a O(mn) solution.
I was also constantly communicating my thought process (Maybe i talk too much?)
I added some assetion at the end to show how i will test the function (maybe i didnt give enough edge cases?)
I added doc string and comments in my code and pretty sure it's pep8 compliant. lol
I tried to be humorous ( okay maybe that is the biggest reason why).
Took the effort to draw out tiny ascii graphs - (maybe he thought that i was a dotard to do that?)

I am very confused because when asked for how I should improve, he said that all is good, looks like i have been practicing etc, you did well yada yada yada......

When the recruiter called I was very happy but unfortunately it was not good news.
Tried to ask for reasons, she said for legal reasons she cant let me know.

Oh well. Nothing to do here. A little upset since I actually thought I did really well.
My only guess is that with so much layoffs happening and a slowing economy, the bar is really high now.
Or maybe i am so awful and obivilious. ( but I do have an offer in hand (startup) and a onsite on the way with another FAAN , so I cant be that bad)
I don't have a CS degree but has a PhD in something related and spend most of my time coding.

I guess there are always things in life you will never get to know.

Anyone had similiar experience?

But I will try again next year and this time round lady luck will be on my side.