FlexTrade Systems Inc. Software Developer interview questions

First took me through an intro call, which was simple enough explaining my career from start to finish. I'm a junior dev, so I focused mainly on my one previously role, talked about arch, day to day and core language uses and application. Recieved a private LeetCode link to complete within 7 days, was told 2 hours to complete but the LeetCode timer was set to 3 hours. Passed 4/5 test cases, took 2h27 to submit the single question. Did a bit of digging after submitting - found this specific problem was not public. Really enjoyed the challenge, but my code must not have been flexible enough (that fifth test case failing caught me so bad and I couldn't get my head round it annoyingly - big fluster). Did not receive next round invite.