NVME drive not working in second slot of Asrock B450

is a hard drive port usually used for SSDs Some SSDs may use SATA 6Gbps still These SATA SSDs use AHCI

2 SSDs are keyed at both M and B positions, so they can fit in SATA slots and PCIe , even if they might not work in the latter NVMe SSDs are keyed only

m2 slot Can I use an M2 SATA in an NVMe slot A slot that can do SATA will have the M key andor B

m2 slot mainboard Yes and its generally written on the manual that which sata ports will be disabled if you are using drive Some motherboards will even