Flexport phone screen

What is the bar at Flexport ?
I had a phone screen with them last week. There were 3 questions in total with each one building on top of the previous one. On LC scale the questions were Medium, Medium-Hard, Hard.
I solved first 2 questions(Medium & Medium-Hard) without any assistance or hints from the interviewer.
By the time I reached the third questions we only had 7 min left in the interview, & I didnt have a clue about how to solve it optimally. I just discussed how I would approach the problem and interviewer seemed ok with it. He said I would hear back soon from recruiter.

A day later I got a generic rejection email from the recruiter.
Are we supposed to solve all 3 questions optimally? Is the bar that high ?

TC: 170k
#leetcode #flexport