There is currently an issue plaguing many BT (and correspondingly Plusnet) customers wishing to play League of Legends. Firstly, I will explain the issue. It can initially appear when trying to log into the LoL client. http://imgur.com/UjHp8W5 If login is successful, which when this issue is in effect, is less than half the time, starting a match will cause another problem. After character selection, the menu client will minimise and the game client will start, usually showing you the team lineups while the game loads. This issue stops me getting to that point. The game client loads, but it just stays as a black screen until I get an error message saying the client could not connect to the server and to check my firewall settings. This happens regardless of if my windows or router firewall are enabled or not. Then I have to quickly close both clients, restart LoL, try to log back in again (which might or might not work) and reconnect to the game (which too, might or might not work). Some games I get back in first try, some games I never get back into. It has been coming and going for months, and because of the nature of the problem, causes the affected user to lose games, lose ranked points and even suffer temporary bans for abandoning matches. This issue is widely known among the League of Legends community with the vast majority of affected users being either BT or Plusnet users playing on EUW, and Riot Games themselves have said that the issue lies with BT. Here is a tweet by the official Riot Games EU twitter account confirming this to another user 2 months ago: https://twitter.com/RiotSupport/status/519948775515631616 It comes and goes, but when it is happening it can last for days. Searching the League of Legends Subreddit on Reddit.com (http://www.reddit.com/r/leagueoflegends) for Firewall issues will show you that many other users are affected and are all coming to the realization that they're all BT or Plusnet customers. Please can this issue be investigated. It has been months.