PC Powers on and off repeatedly

[pontiactaylor110ce]

Trying to diagnose why my computer will(when shut down) start to power it self on for a split second, then turn off. And repeat.

The psu and mobo are new. Cpu cooler is also new. Everything else has been used for a year.

i5 6600k
MSI Gaming X GTX 1070
Rosewill Glacier 600 watt
16gb 2x8 DDR4
MSI Z270 MORTAR Motherboard
Dark Rock Pro 3
Core v21

Any help is very much appreciated!

 

[superninja12]

you forgot the insert both 24pin mobo cables probably to the psu, its a cable mistake.

 

[pontiactaylor110ce]

you forgot the insert both 24pin mobo cables probably to the psu, its a cable mistake.

I'm confused in what you mean. The 24 pin is plugged into the motherboard. What do you mean both 24 pin cables? Thanks

The computer turns on and runs fine, it's just when it is off is when it starts cycling the power on and off.