Hearing a sound after a mob has been killed

Im new to paper. I mostly play on vanilla servers. but because of lag I thought it would be nice to transfer my server from vanilla to paper and i have set some anti lag parameter in the .yaml file. But since having this server everytime me or another player in my server kills a mob. They hear somesort of a breaking block sound. Im sorry guys don’t know the name of the exact sound. But where can I turn this off. It is kind annoying when in big fights with loads of mobs.

Never have problem like that. breaking block sound? what sound? zombie break wooden door?
or Herobrine :rofl:

Really that never happen to me…