Ipv6 address for HiPad Max

How do I get an ipv6 address for my HiPad Max device using SLAAC? My home network uses IPv6. All devices laptops, NAS, several tablets, MTK phones (mediatek) get the ipv6 address that my configured radvd server on the router gives out without problems. Recently bought a HiPad and can’t get any address except a local one (from the fe80::/112 range). How to set ip6 properly?