PowerEdge R750 not boots and has an error "NvmExpress: NVMe device not ready."
Figure 1
TSR log checks the slot6 and 7 NVMe SSDs can detect, PCIe slot2 installed a third card.
Figure 2
Lifecycle Log check has a device not detected: NVIDIA Network Adapter - A0:XX:XX:XX:XX:FB(NIC in Slot 2 Port 2)
, New device detected: PCIeSSD(PCIe SSD in Slot 2)
Figure 3
It seems the PCIe slot2 third card Port 2 detected a wrong device caused by not boot.
The user replaces the PCIe slot2 third card, and the issue was solved.