Mixelsrock

So I set up my Minecraft server but something is wrong any block I place will immediately disappear I also use the tech guns mod and the guns don't fire there is also a really powerful sword that came with a weapons mod that is supposed to do 24 damage but instead it does almost no damage at all, the entire forge server works fine and I can place and destroy the blocks that aren't from mods but the mods just don't work, you can still see them in your inventory but when you try to place or use nothing happens there is one mod that works which is the mobends mod but I don't think that really counts and me and my brother tried to join together and it all worked but when either of us held something that was from a mod nothing would be there and I really need help