I need help with my server

I have just started a new 1.13.2 server and when i try and play it does not let me break blocks. it destroys the block then half a second after it replaces it like some sort of world guard. i also have a problem with commands, when i type any command it say "An internal error has occured while attempting to preform this command". any help would be great thanks

Quote from Twenty

1. I don't trust 1.13. If all suggestions below this one fail, try reverting to 1.12.2

2. Make sure you don't have the standard, outdated Essentials. Use EssentialsX

3. Installing EssentialsX allows Essentials to stay and run properly. If you wish to do this, delete both Essentials AntiBuild and EssentialsProtect

thanks mate i'll give it a shot. can you please tell me what antibuild and protect do