Board Thread:Bug Reports/@comment-70.208.4.39-20160425212446/@comment-27516710-20160426191741

Blocks not breaking is an indication of severe lag - if you are playing in SP then your machine has to run both the server and client at the same time and if you are running into issues like that it means your computer can't keep up. If you press F3 while using MC it will show you the version of Forge in the upper right corner. Which one are you using? You should try using Fastcraft with this - it can really help with the LOTR mod.