How Can I Stop TNT From Blowing Up?

I have a Minecraft server, and I want to know how to the ban TNT so it doesn't do exploding damage. I have tried Essentials Protect and BanITEM, and did all the config correct multiple times. I tried all the banning items, but when you place TNT it blows up right when you place it.

To disable mob griefing (basically stop any mob from causing damage to the ground, which includes creepers, the wither, and the ender dragon) type this command in chat:

/gamerule mobGriefing false

For stopping TNT from exploding, it's a little more involved. Basically, you create a hopper loop clock, place any item in one of the hoppers and it should automatically start. Make sure you put a command block on the output (image for the clock is posted here:)

And the last step is to input this command into the command block:

/kill @e[type=PrimedTnt]

And Voila! No more TNT explosions! This command will delete the TNT the second it gets lit, removing it from the game before it gets the chance to explode!