PC not booting up after installing rx570

[MarcJustCons]

Hey guys, i bought rx570 4gb (gigabyte). But after installing and plugging the 8pin (4+4pin). It wont boot up. But It does boot up without rx570. I also tried to turn on my pc without plugging the 8pin to check if rx570 is not working. But it does light up. Any help?


Specs:
AMD Fx6300
GIGABYTE GA78LMT S2 MOBO
GIGABYTE RX570
x2 8Gb HYPERX 1866MHZ
516watt PSU with (4+4 pin) and (6pin)