Ds1819+ pci-e Nvme card compatibility

[cwalkin]

Hey all
I have a Ds1918+ with 7.1 and have tried 2x different Pcie cards with 2x same size Nvme drives.
The issue I’m having is that it only sees 1x Nvme and only allow read cache.
Are these locked down to only Synology Pcie cards?
If not can anyone suggest one that works?

Thanks

Dan