TikTok Creator Operations Manager interview questions

I proceeded through two rounds and even managed to complete a case study, but after the third round, they just sent me a rejection email without any specific reason or clarification. In my experience, it's weird because it wasn't the first step, and usually, when you negotiate with companies for more than 2-3 weeks, they must give you a call and explain their position or at least write a more detailed email. This time, it was quite an awkward, generic email, as if I hadn't even proceeded to the fourth round and we didn't know each other

I had an initial 30min phone interview with the recruiter, followed by an interview with the head of the department on a video call. This was straight forward - telling me more about the role & department and expectations and asking me basic questions on my experience. Finally, I had to complete a task and then present it back to two people on a video call, where they asked me questions about my response.