IPv6 nd trouble

Hi all! I configured 6to4 interface to my tunnel-broker. Add routes and addresses. But I have one trouble - my clients not obtain Global IPv6 addresses via nd. If I setup it manually on clients PC - all working fine.

My configuration:

/ipv6 address
add address=2a01:d0:ffff:c37::2 interface=sit1
add address=2a01:d0:8c37::1/48 advertise=no interface=bridge-local
/ipv6 firewall filter
add action=drop chain=input in-interface=ether1-gateway
add chain=forward comment="allow xmpp file transport for all" dst-port=8010 in-interface=sit1 out-interface=bridge-local protocol=tcp
add chain=forward comment="accept ipv6 torrent for all" dst-port=6881 in-interface=sit1 out-interface=bridge-local protocol=tcp
add chain=forward comment="accept ipv6 torrent for all" dst-port=6881 in-interface=sit1 out-interface=bridge-local protocol=udp
add chain=input comment="Router - Allow IPv6 ICMP" protocol=icmpv6
add chain=input comment="Router - Accept established connections" connection-state=established
add chain=input comment="Router - Accept related connections" connection-state=related
add action=drop chain=input comment="Router - Drop invalid connections" connection-state=invalid
add chain=input comment="Router- UDP" protocol=udp
add chain=input comment="Router - From our LAN" in-interface=bridge-local
add action=drop chain=input comment="Router - Drop other traffic"
add action=drop chain=forward comment="LAN - Drop invalid Connections" connection-state=invalid
add chain=forward comment="LAN - Accept UDP" protocol=udp
add chain=forward comment="LAN - Accept ICMPv6 " protocol=icmpv6
add chain=forward comment="LAN - Accept established Connections" connection-state=established
add chain=forward comment="LAN - Accept related connections" connection-state=related
add chain=forward comment="LAN - Internal traffic" in-interface=bridge-local
add action=log chain=forward comment="LAN - Log everything else" disabled=yes log-prefix="Log IPv6"
add action=reject chain=forward comment="LAN - Drop everything else" connection-state=new in-interface=sit1
/ipv6 nd
set [ find default=yes ] advertise-dns=yes disabled=yes interface=sit1
add hop-limit=64 interface=bridge-local
/ipv6 route
add distance=1 dst-address=2000::/3 gateway=2a01:d0:ffff:c37::1

The similar configuration works for me before with Hurricane Electric tunnel broker. But I decided switch to NetAssist. Because it’s in UA-IX(lower latency for me) and with HE I had trouble in google services(they thought I was from Germany).

I solved this trouble. I tried to allocate /48 subnet via nd, but the most OS not want obtain addresses from /48 subnet by default, so I split /48 to many /64 subnets and allocate addresses to clients from /64 subnet.