I am having this issue as well. ATlauncher, Twitch Launcher and CurseForge all get errors when trying to download Pixelmon. They mention "an expection occured during a WebClient request". I was told it was something wrong with my antivirus, but I don't have anything apart from windows firewall and I can't figure out whats going wrong if that is the reason. Someone please help as I am greatly confused.