Technical phone screen was conducted by only one software engineer. There was no reason or explanation provided for the result, such as not being suggested to move on. This result eventually blocks the candidate, perhaps permanently. Can one person, whose expertise is uncertain, and a single technical problem-solving question (which I unfortunately did not practice, unlike other candidates who might have) truly decide an applicant's capability?

General technical coding questions, but I have no idea what they wanted or what I missed.