8 pin connector not connecting

[kriod]

Im helping my friend with his pc and i encountered a problem
The psu has two 6+2 and one 8 pin connector and none of them are able to connect to the 8 pin cpu power slot
Psu : corsair cx 750
Motherboard : asus z270 p
Its my first time building a pc

 

[turkey3_scratch]

That PSU has 4 PCIe cables and 1 CPU power connector.

 

[smorizio]

it a known issues with that power supply. buy a 8 pin cpu 12 inch extender. see if it fits or use just 4 pins of the 8 pin connector. or swap power supply.