Glassdoor interview reviews were right when they said the company wastes your time even after taking 5-6 rounds but i chose to ignore that and went ahead. After spending ~3.5 hours finishing up all their 5-6 interview rounds and the HR even acknowledged that my technical rounds went well and they themselves don't know what went wrong. Initially I had a good impression talking to the interviewers and their CTO and VP seemed friendly. They even explained me what I'll working on and stuff but the next day a generic rejection email without any explanation. Have been following up for a feedback for a while now but haven't received yet. Will update this if I ever receive a satisfactory feedback from them about what went wrong. For now, all I would say is don't waste your precious time as they might not have the budget to hire the right candidate and are just using you for benchmarking purposes.