Cadence Design Systems EDA Software Engineer interview questions

Contacted by HR to schedule an interview with the manager. I applied online and got the response in 15 days. The questions were staright forward and i answered them well, even the manager appreciated my answers. But they sent me a reject mail after making me wait for 3 weeks and the HR did not even reply for my follow up email. Overall the questions were easy but the manager and the HR seems irresponsible.

It was a 30-minute phone interview. The hiring manager asked very basic interview questions. He mainly asked questions based on C++ programming Did not need employee referral even though I was applying for entry level position.