Darktrace Devops Engineer interview questions

I did the process for Cambridge, UK. First the recruiter sells you the role. Second you do the first informal interview, fine. Third you make a technical task as home-assigment Fourth silence , they ghosted me. Not even a simple email. This happened to me twice, in 6 months! When another recruiter asked me again, I had to refuse. I don't understand why this company decides to ghost candidates without a simple clue.