ClassiCube

So, I'm new to this forum and am not sure if this is where I'm supposed to post my issues with the game. The problem is that my game can't sign me in, which means no servers, can't check for updates and it can't even download the default texture pack (which is I assume the only thing it downloads nowadays, considering that singleplayer works fine, expect there's no textures). Now I can't understand as to why it's not working, because it worked perfectly until recently. Please help.