Forcepoint Sr. Software Engineer interview questions

I had 4 rounds of interview, first 2 were technical, next was techno-managerial. I cracked all the rounds, In the last round the manager even said I would talk to HR and we can release the offer letter but post that, for a week there was no response from HR, upon inquiry he mentioned they were having hands-on meeting hence things would be delays by a week, so I waited for a week and still no response, I kept dropping mails at a week's interval for the progress, there was dead silence for 2 months. and finally they came back saying that there is not progress on the position that I was interviewed