PLX 500 Clicks and Pops

Hi,

I am a new vinyl player please help, I just bought the PLX 500 and connected phono to DDJ phono input. Switch on plx is on phono, and on ddj too. I keep getting crackles and pops on all my vinyls. In the beginning during breakdowns all the time. If im not playing anything, and I increase the gain on that channel I can hear humming and noise.

Using rekordbox, as far as Im aware there is no grounding required for the PLX. I also dont even know how to do it.

There is something wrong, can you please assist? Maybe something wrong with headshell?