DSFederal Project Manager interview questions

They reached out to me multiple times for a few weeks trying to set up an interview. I reached back out and had a call with the recruiter. I then had a video interview with the person I would be replacing. The interview went great and the recruiter got back to me and said the feedback was great. A few days later I was set to have a video call with the CEO and a few other people in management. I was expecting to get an offer and 15 minutes before the call they canceled and the recruiter said they weren't interested in rescheduling. This really threw me off as I was expecting to get an offer and they just bailed and didn't give me a reason which was unprofessional.