Discover interview questions

I have applied through LinkedIn on Feb 13 and i have been done with screening round with recruiter ,it was good. Later he scheduled in the screening round the first round of interview it was total technical, and eventually it was 1+4 rounds, the 4 rounds where behavioural mixed architecture and whiteboard related questions. 1st round Microservices, SpringBoot, coding related syntax, basic java questions. (1hr) 2nd round was he gave me scenario i need to design architecture and some basic java questions in last 5 minutes (1hr) 3rd round Microservices based and behavioural based (1 hr) 4th round Whiteboard, he gave me an scenario ask to design architecture and later asked few questions related to that and write an basic overview code (1hr) 5th round behavioural questions (45 min) 4and 5th round was on same day with 1 hr of gap Still no idea why it was rejected. I have done well.

HR sent an email saying it would 5 rounds of interview. 1- technical, 3 behavioral, 1- whiteboard. HR sent 3 invitations for technical round and didn't confirm the interview time. Attended 2 interview slots but no one joined the interview. Rescheduled the interview after 2 weeks and again no interviewer joined the session.