I was on the list for whatever reason. However I was still missing lots good time when I was with the company a fews years back. It was a fantastic team and esepcially one of the guys who was doing some funny stuff ever single day, but he could get things done. There were some challenges in that team, by looking back, we could probably done better. For example, now it is time for your to demostracte what you have learned since you left the company and share the thoughs with team and so on.
I think the key is that you probably had some weakness, which was pointed out by your previous boss or somebody in the company. If you coudln't provide reasonable answer to mitigate that during interview, the hiring manager would have concern and not willing to extend the offer.