Board Thread:Bug Reports/@comment-52.206.255.185-20170925120145/@comment-27200931-20170925213921

You are using the wrong forge version. Grab the recommended forge version from this page: https://files.minecraftforge.net/maven/net/minecraftforge/forge/index_1.7.10.html

Also make sure you're using Minecraft 1.7.10 and not Minecraft 1.12