Faulty PSU?

[Swiftx]

Hi everyone, Im having a slight issue with my pc where after performing a shutdown the pc wont be able to turn on again unless i turn off the wall socket completely for about 5 sec and turning it back on.

 

Here are my PC Specs
Asus Z370-P
I5 8600K
Zotac GTX 1070 AMP
8 GB RAM
Kingston SSD v300 240GB
Kingston SSD v300 240GB
Seasonic M12ii 620W

[Guest]

Could be the PSU.  Could be the motherboard.