Quantitative Researcher

I applied online, and was contacted by a recruited within two weeks. Two phone technical rounds approximately one week apart, after which I was informed of a rejection in a generic email. No other feedback was given. I was a little surprised because I thought I had done quite well in both rounds. If I had to guess, it's that I took too long to answer the questions - we probably didn't get through all of them, although this was not made clear to me during the interview.