MP 7,1 M.2 SSD PCIe Cards in Mac Pro 7.1 flash amber twice

[Mac3Duser]

Hi,
this week-end, I installed an additional PCI e card with a M.2 SSD nvme in my Mac Pro, and I had the flash amber : the mac Pro didn't start.
on the apple support website I read this :
"If your Mac Pro doesn't start up and the status indicator light flashes amber twice after installing a PCIe card, the card might not be compatible with your Mac Pro or you might have too many 32-bit PCIe cards installed.
If you recently installed one or multiple PCIe cards, remove each card one at a time and try turning on your Mac Pro after each card removal. "
I know the card is compatible because I had the same inside, and with only one the mac pro starts, so I would like to know if this is the "too many 32-bit PCIe cards installed" issue or something else.
the card is the sabrent https://sabrent.com/products/ec-pcie
there is no controller, the two cards are ok, but impossible to start with two.

 

[Bigwaff]

Which slots are you using when you have both cards installed? Do you have any Thunderbolt devices connected to your MP? W/out the second card installed, have you checked your avail PCIe bandwidth using Expansion Slot Utility?

 

[Mac3Duser]

I tried on slots 5, 6, 7
thunderbolt is used for Screen, but when I tried, It was only connected to hdmi
I checked the Expansion slot utility but the nvidia is not seen in Mac OS, and if I remember well, slots 1 and 3 are CPU pcie lanes, and the others are PCIe Switch, but this card is only pcie X4

 

[Bigwaff]

Share screenshot of Expansion Slot Utility w/out second card installed. Nvidia in Slot 3? Have you tried manual reallocation of the pools?