Enable FHS globally for ND inspection to work.
Use this procedure to enable Neighbor Discovery inspection on a port
enable
configure terminal
interface GigabitEthernet {slot/port[/sub-port][-slot/port[/sub-port]][,...]}
Note
If the platform supports channelization and the port is channelized, you must also specify the sub-port in the format slot/port/sub-port.
ipv6 fhs nd-inspection enable