My roommate and I are also getting the issue (even when only one of us is trying to play). What's going on here, Riot? Please fix this.
To be specific, after everyone's locked in and the countdown finishes, the "LEAGUE of LEGENDS" splash screen appears. It stays there for a very long time. If I mouse over it, my mouse cursor turns into the circular "loading" cursor. Eventually, it makes a Windows ding sound and a window appears behind it (because the splash screen is set to "always on top") with the title, "Failed to Connect", and the text, "Unable to connect to the server. If you have a firewall, it may be blocking the connection. Please refer to your firewall's documentation. Would you like to retry the connection?". It has a "Retry" button, a "Cancel" button, and the standard Windows "X" button in the top-right corner. If I click "Retry", the window disappears and the splash screen remains, repeating the cycle. If I kill all the LoL-related processes using Process Explorer and try logging in again, sometimes it allows me in and gets to a loading screen and sometimes it doesn't, preferring to do the same thing with the splash screen and eventually "Failed to Connect" window. Please fix your network and loading code.
I am a network administrator and I understand what a firewall does. I have Windows 7's firewall disabled. I am using a Billion BiPAC 7800N gigabit router (said to be among the most stable and consistent routers in existence) set to forward all ports to all machines on my LAN (default setting). LoL worked perfectly and consistently until yesterday when I first saw this issue. None of my hardware or software changed between the time it worked consistently and when I first started seeing this issue.
I live in Toronto, Ontario, Canada and my ISP is Acanac. I have their 28 Mbps cable internet plan. Acanac uses the Rogers network for its cable connection to my home. Acanac is also somehow related to Distributel, but I'm not sure in what way.