So, I sent an e-mail to the person who interviewed me asking what I could do to improve my interviewing skills and other such related questions and, as of yet, have not received a response. Shortly after HR informed me that I wasn't getting a second interview, I asked my supervisor if she could find out if I could take Series 6 (since a lot of positions I would like want the person to have this at some point) so I could have a competitive advantage when interviewing for other jobs. After this, my supervisor inquired about why I didn't get the position with the guy who interviewed me and he gave her an answer. That kind of shit really pisses me off.
Note: This interview was for an internal position