Hi, I have a big problem with my 6x MSI GTX 1070 cards. Below I give details of the subassemblies:

Motherboard: Asus Prime Z270-A
Processor: Intel Pentium G4560
Memory: 8GB Kingston Hyper X DDR4
Power Supply: 2x be quiet 700W Straight Power 10
SSD: 240 GB
Risers: 6x PCI-E1x to 16x with 6 pin power and usb port

Risers are visible in the photo.


Bios has been updated to the latest version.
Operating System: Win 10

Cards are visible in device manager, but with error status 43.

When connecting one card directly to the motherboard, the card is visible on the system with the drivers installed.
When I connect another card through the riser I still have error 43.

Is it due to bad risers? If so, what do I have to buy?
Has anyone encountered a similar problem?
Is there a better way to install Ubuntu?

Thank you in advance for your help