Dana Rebecca Designs interview questions

Applied for the position online, was emailed for an interview within a day or two. Had (3) phone interviews, first with the President and then with others in the position I was applying for. Following the (3) interviews, I was told everyone was really impressed with me and they would like for me to come in for a final, 4th interview, and to see the office, and see how I gel with the staff. All seemed to go well, and within 15 minutes of leaving the interview, was sent a generic email through ZipRecruiter stating "thank you for your time, but.........." At first, I thought it might be a fluke, as all interviews seemed to go well. I directly emailed the President (small company) and the next day he responded with, "yes, I sent the email." I thought this to be incredibly unprofessional after 4 interviews.