When tp link ethernet splitter connected rig cannot connect to internet?

hi having trouble connecting to the server when i plug the ethernet cable from my tp link splitter but when i plug directly into wall socket bypassing splitter it connects fine ,is there a certain setting i have to apply or am i missing something ?
this is the splitter i am using https://www.amazon.co.uk/gp/product/B0766D8HZ3/ref=ppx_od_dt_b_asin_title_s01?ie=UTF8&psc=1
all the lights flash on the motherboard indicating it has a signal
any help would be appreciated