Looking for logging into the Lol Backround site and are not getting the correct working link for it? In such a case, you can use the links given here by searching your desired login page in the search box. If the page is present on our website then you will get all the links related to the Lol Backround site. After that you can login as usual with your login credentials.
https://na.leagueoflegends.com/en/featured/league-displays
https://na.leagueoflegends.com/en/news/community/community-spotlight/find-your-favorite-past-login-screens
https://euw.leagueoflegends.com/en/news/community/community-spotlight/find-your-favorite-past-login-screens
http://forums.euw.leagueoflegends.com/board/showthread.php?t=17274
https://boards.euw.leagueoflegends.com/en/c/alpha-client-discussion-en/EAj41QXJ-login-screens-change
https://boards.euw.leagueoflegends.com/en/c/bug-reports-eu/otrEo6hj-profile-background-changing-patch-89
http://forums.na.leagueoflegends.com/board/showthread.php?t=1382407
https://na.leagueoflegends.com/en/media/art/wallpaper
https://support.riotgames.com/hc/en-us/articles/207525756-Setting-custom-League-screensavers-and-wallpapers-League-Displays-
http://www.rediscussed.com/tag/lol-desktop-login-background/
https://www.riftherald.com/lol-gameplay/2018/5/2/17312612/lol-customize-background-profile-bug
http://support.lol.garena.com/en_SG/articles/406
https://soundcloud.com/violentrl/worlds-2016-login-screen