Citi AVP-Analyst interview questions

I applied online, several days later got a phone interview with a recruiter and then a director. The questions were very easy, introducing my background which was relative to this position, and a very simple coding question. The director seemed to be very nice. And 20 minutes later I received a rejection letter. Everything just happened so fast that I couldn't notice what was wrong with me. One reason I could guess was when we were talking on the phone the connection was really bad, which made me an unprofessional candidate. But it was really not my phone's fault.