Can't get dhcpv6 client working

Hi! Can't get dchcpv6 client working. My ISP switched PPPoE to DHCP.
With PPPoE it works great, just created ipv6 vlan and it's just work.
IPv4 dhcp work great, no issues, but when i create same WAN (device) dhcpv6 client, it's just don't obtain IP.
Tryed Alias WAN_6 with WAN (ipv4), also not work, not obtain IP.
What is correct way to make dhcpv6? Should it be alias with main WAN?