Sometimes it can happen, especially with modpacks, that you can neither go through the Nether Portal nor through the Ender Portal. This is a bug you can easily fix. Log in to the GPORTAL web interface and select your Minecraft server Stop your server and create a backup  Once this has been created, connect to your server with an FTP program (the access data is on the status page of your server) Go to your world folder (this folder has the same name as your world name). There you will find two files: level.dat and level.dat_old Remove these two files and start your server. Don’t worry, these two files will be recreated by the game to match your world. You should now be able to go through the Nether or Ender Portal.