Question No post even after LED debug lights cycle check

[Atlas_MC]

Hey guys, struggling to get new build to post. MSI b550 gen 3 (claims to be ryzen 5000 ready...) cpu is ryzen 7 5800x, gpu is gtx 1080 and two sticks of 8 ram. With all components in no debug leds stay on (it cycles through them on start up but then all go off once checked) I have tried a bios update with USB a few times made no difference, it does the whole flashing thing for 5 mins restarts itself and back to no display. Greatfull for any advice

 

[rgd1101]

full system spec? include brand and model of the psu

 

[Atlas_MC]

full system spec? include brand and model of the psu

MB: MSI B550 gen 3
Cpu: Ryzen 7 5800x
Ram: 2 x 8gb corsair vengeance LPX
Gpu: GTX 1080
Psu: 600w aero cool integrator 80+
Drives: 2 x ssds

 

[letmepicyou]

Did you try simply resetting the cmos/bios?
How certain are you that you don't have any motherboard standoffs where they don't belong? Does it post out-of-case?