couldn't enable TSO on a physical NIC?

hi folks,

i'm trying to turn on the TCP Segmentation Offload(so-called TSO) on my phisical NIC in ESXi host.

the environment is  ESXi 6.5.0, build 5310538

and the physical NIC were all "Intel Corporation 82599EB 10-Gigabit SFI/SFP+ Network Connection"

driver is ixgbe

i followed this vmware kb and use SSH to command the hosts:

ethtool -K vmnic0 tso on

but i got this result: Cannot set device tcp segmentation offload settings: Function not implemented

(addtionally, i couldn't enable linux guest os TSO, too)

i've tried to search vmware kb but didn't help...

does anyone know how to fix this?

so much appreciate!