I have been experiencing an issue, whenever I try and join the DMU server but it says ("java.io.IOExeption:an existing connection was forcibly closed by the remote host), I am not really sure what to do, I might think that the server is closed down, but if anybody has any ideas, please help me.
You need to update your version of forge to 14.23.5.2857 or higher
It can be downloaded from here: https://files.minecraftforge.net/net/minecraftforge/forge/index_1.12.2.html