Hello my friends. I want to play Minecraft with my friends. I am using Minecraft 1.12.2 because of the mods we want. I download Minecraft server file and I created a server. I arranged it and made some setting such as onlinemod=true to false and server ip setting in the server..properties. We connect with a Hamachi network. When my friends tried to join my server, they see this error "Internal Exception: java.io.ioexception". What should I do, I will go mad please help me.