S4820 with VLT cannot ping other peer management IP(vlan)

Hi All

Can I ask about this my S4820T with VLT cannot ping other peer management IP address, connected to my core switch(S4810) also in VLT, from switch to switch I can ping and manage all ip address of my S4820 but if I connect my laptop in my access switches, all the management IP already communicating except with one ip in my S4820T(vlt)

Thanks in advance

BRENT