Assign VLAN to host by MAC, new-vlan-id feature

Hello,
I want to assign specific VLAN to hosts based on their MAC address. So i configured a compatible hardware (RB1200) , added a VLAN 500 on ether1, put an IP and DHCP server on that VLAN and added a switch rule to redirect MAC to this VLAN.

When i activate DHDP client on the host, I don’t get any IP; on the DHCP server, I see that lease is offered but not bound and I got warning messages.

00:32:45 dhcp,warning dhcp1 offering lease 192.168.51.254 for 6C:3B:6B:A3:04:87 without success

What am I missing ? here is the RB1200 export

/interface vlan
add interface=ether1 name=vlan-500 vlan-id=500
/ip address
add address=192.168.51.1/24 interface=vlan-500 network=192.168.51.0
/ip pool
add name=dhcp_pool0 ranges=192.168.51.2-192.168.51.254
/ip dhcp-server
add address-pool=dhcp_pool0 disabled=no interface=vlan-500 name=dhcp1
/ip dhcp-server network
add address=192.168.51.0/24 gateway=192.168.51.1

/interface ethernet switch port
set 4 vlan-header=add-if-missing
set 5 vlan-header=add-if-missing
/interface ethernet switch rule
add new-vlan-id=500 new-vlan-priority=5 ports=ether1 redirect-to-cpu=yes src-mac-address=6C:3B:6B:A3:04:87/6C:3B:6B:A3:04:87 switch=switch1