I found this on the website dont know if it will help
As you’ve all probably noticed, the Minecraft Classic server list over at
http://minecraft.net/classic/list has been lately getting spammed, and this was causing all sorts of lag when signing in and selecting servers from the list when using the WoM Game Client.
To rectify this issue the WoM Game Client now pulls down a validated list of servers from WoM Direct instead of the official list from Mojang (by default). You may toggle this behaviour by deselecting “Valid” at the login screen, which will likely cause your client to crash until this mess is sorted out Mojang-side.