I successfully finished an interactive project for one of my clients. We did a great job and finally I had to install the system on their server. I received the FTP and MySQL information from their IT team, but when I uploaded all my files the site didn't work at the first time. The server didn't show any errors and I wasn't able to find out the problem.
I'm working on a year old application written in node. There is twitter streaming API implemented and it worked before a couple of months. These days we moved the site on another server and I found that it is not working anymore.