[siva_]

May I please know what kind of technical interviews you've had? Have you tried sending a friendly email and asking the interviewers for reasons? Do they have issues with your style of solving the problems? Like, do you hole up and do it all by yourself or do you walk them through and ask clarifying questions along the way?

Even if the manager likes you, HR might gatekeep due to employment not being a perfect track record. Maybe sending HR an email thanking them for their help along your journey so far and asking why you didn't make the final cut may also give you some insight.