What's wrong with my server?

So I'm using a server spawn I got off of planet minecraft, everything is all fine and dandy, nothing seems out of the ordinary. I start hitting blocks with my fist and I see
"You are not permitted to interact with GRASS."
Does anyone know what's wrong? This has happened to me before but so I deleted the world and everything was back to normal.
Btw, it doesn't say this if I have opped myself

 

Install a permissions plugin?

OP Yourself?

set the spawn protection radius from 16 to 0 in the config?

 

set the server yourself instead of downloading plugin prepacks which you dont even know what they contain?

 

i have to concur on that one

 

Who exactly said I did that?

 

kind of sounded like you did, because the message you described is an error of that you have no permission for the node essentials.build.interact.3 coming from essentialsantibuild.jar