Problems with BSR64K and DHCPv6 Server (ISC KEA)

Hi,
we are having a situation where we want to offer ipv6 directions from a DHCPv6 KEA Server, this one is located in an different network from the CPE that we want to offer the IPv6, so we are using the BSR as a relay-agent. The solicit package gets to the BSR and lates it sends the relay-forwarding package, but when the servers responds with the advertise package, it never gets to reach the BSR.
The following lines shows a debug in BSR64K:

[03/22-14:32:42.79- 07:Dhcp6Relay]-D- Remote ID: 00 13 71 b8 ff c0
[03/22-14:32:42.79- 07:Dhcp6Relay]-D- Enterprise ID: 4491
[03/22-14:32:42.79- 07:Dhcp6Relay]-D- Length: 10
[03/22-14:32:42.79- 07:Dhcp6Relay]-D- Tag : Remote ID (37)
[03/22-14:32:42.79- 07:Dhcp6Relay]-D- DOCSIS version number 3.0
[03/22-14:32:42.79- 07:Dhcp6Relay]-D- Suboption 1026: CM MAC address option = 00:13:71:b8:ff:c0
[03/22-14:32:42.79- 07:Dhcp6Relay]-D- Enterprise ID: 4491
[03/22-14:32:42.79- 07:Dhcp6Relay]-D- Length: 22
[03/22-14:32:42.79- 07:Dhcp6Relay]-D- Tag : Vendor-specific Information (17)
[03/22-14:32:42.79- 07:Dhcp6Relay]-D- Value: 28 00 06 20 e6 00 00 0a 00 00 00 00 00 00 00 01
[03/22-14:32:42.77- 07:Dhcp6Relay]-D- Length: 16
[03/22-14:32:42.77- 07:Dhcp6Relay]-D- Tag : Interface ID (18)
[03/22-14:32:42.77- 07:Dhcp6Relay]-D- Value: 00 18 00 17 00 11 00 27
[03/22-14:32:42.77- 07:Dhcp6Relay]-D- Length: 8
[03/22-14:32:42.77- 07:Dhcp6Relay]-D- Tag : Option Request (6)
[03/22-14:32:42.77- 07:Dhcp6Relay]-D- Vendor Class Data:MSFT 5.0
[03/22-14:32:42.77- 07:Dhcp6Relay]-D- Enterprise number: 311
[03/22-14:32:42.77- 07:Dhcp6Relay]-D- Length: 14
[03/22-14:32:42.77- 07:Dhcp6Relay]-D- Tag : Vendor Class (16)
[03/22-14:32:42.77- 07:Dhcp6Relay]-D- Value: 00 08 6e 75 6e 65 7a 2d 50 43
[03/22-14:32:42.77- 07:Dhcp6Relay]-D- Length: 10
[03/22-14:32:42.77- 07:Dhcp6Relay]-D- Tag : Fully Qualified Domain Name (39)
[03/22-14:32:42.77- 07:Dhcp6Relay]-D- T2: 0 sec
[03/22-14:32:42.77- 07:Dhcp6Relay]-D- T1: 0 sec
[03/22-14:32:42.77- 07:Dhcp6Relay]-D- IAID: 11544249
[03/22-14:32:42.77- 07:Dhcp6Relay]-D- Length: 12
[03/22-14:32:42.77- 07:Dhcp6Relay]-D- Tag : IA_NA (3)
[03/22-14:32:42.77- 07:Dhcp6Relay]-D- Link Layer Address: 54 42 49 f3 ec 47
[03/22-14:32:42.77- 07:Dhcp6Relay]-D- Time: 23952f99
[03/22-14:32:42.77- 07:Dhcp6Relay]-D- Hardware Type: Ethernet (01)
[03/22-14:32:42.77- 07:Dhcp6Relay]-D- DUID Type: 1
[03/22-14:32:42.77- 07:Dhcp6Relay]-D- Length: 14
[03/22-14:32:42.77- 07:Dhcp6Relay]-D- Tag : Client ID (1)
[03/22-14:32:42.77- 07:Dhcp6Relay]-D- Value: 0c 1c
[03/22-14:32:42.77- 07:Dhcp6Relay]-D- Length: 2
[03/22-14:32:42.77- 07:Dhcp6Relay]-D- Tag : Elapsed Time (8)
[03/22-14:32:42.77- 07:Dhcp6Relay]-D- Transaction ID: ec621f
[03/22-14:32:42.77- 07:Dhcp6Relay]-D- Message type: DH6_SOLICIT
[03/22-14:32:42.77- 07:Dhcp6Relay]-D- Length: 88
[03/22-14:32:42.77- 07:Dhcp6Relay]-D- Tag : Relay_msg (9)
[03/22-14:32:42.77- 07:Dhcp6Relay]-D- Peer address: fe80::9027:82c9:1a51:86c7
[03/22-14:32:42.77- 07:Dhcp6Relay]-D- Link address: 2800:0620:e600:000a::0001
[03/22-14:32:42.77- 07:Dhcp6Relay]-D- Hopcount: 0
[03/22-14:32:42.77- 07:Dhcp6Relay]-D- Message type: DH6_RELAY_FORW
[03/22-14:32:42.77- 07:Dhcp6Relay]-D-RELAY-FORWARD message sent to server 2800:620:e600:c::2, CPE mac-address: NULL,ifid = 11, imIndex = 9, tid = 0, schSlot = 4, clsfyKey = 0, macSlotFlag=0, isDhcpReqFlag=0
[03/22-14:32:42.77- 07:Dhcp6]-D-CPE mac-address: NULL ifid = 11, imIndex = 9
[03/22-14:32:42.77- 07:Dhcp6]-D-Received SOLICIT message from fe80::9027:82c9:1a51:86c7, interface name virt,from ifindex 11, tid = 0, schSlot = 3, clsfyKey = 0, macSlotFlag=0, isDhcpReqFlag=0