Brightedge Technologies Project Manager interview questions

I submitted my resume and got a call from HR to set up an interview. I spent a half hour on the phone during the interview, at which time I was told they wanted to follow up with an in person interview with the manager. I went in and spent several hours with several people, thinking the interview was going well. Then the next day HR called to tell me they were no longer interested, but when I questioned them about what they didn't like there were not able to point to anything specific. Not one thing. They said "I don't know why" . Really? That is very unprofessional to not be able to give a reason, and more than a little suspicious. SO GLAD I did not get an offer now!