Delegated-IPv6-Prefix

Hello. I'm trying to include Delegated-IPv6-Prefix attribute to reply, here is contents of radreply table: id | username | attribute | op | value ----+----------+-----------------------+----+------------------------------------------------------------------------------------------------------------------------ 19 | test | Delegated-IPv6-Prefix | = | fc00:1:2:2::/64 But it rejects Access-Request and writes to log: rlm_sql: Failed to create the pair: Invalid octet string "fc00:1:2:2::/64" for attribute name "Delegated-IPv6-Prefix" By the way it successfully replies with Framed-IPv6-Prefix which is ipv6prefix type too. So how can I pass Delegated-IPv6-Prefix ?