Public key issue

[Sunnyday]

I have trouble with using public key.
Drobear server is running on openwrt
Version is 0.48
Client is running on linux
  version 0.48.1 with debug option.
I created key with dropbearkey.
I copy public key to ~.ssh/authorized_keys
juh2# ls -la /root/.ssh/authorized_keys
-rwx------    1 root     root 213 Nov  1 23:51 /root/.ssh/authorized_keys
juh2#

I run client command:
./dbclient -i id_rsa.db -p 23 root at juh  -v
...
TRACE: <- MSG_USERAUTH_FAILURE
TRACE: enter recv_msg_userauth_failure
TRACE: enter cli_pubkeyfail
TRACE: enter sign_key_free
TRACE: enter dsa_key_free
TRACE: enter dsa_key_free: key == NULL
TRACE: enter rsa_key_free
TRACE: leave rsa_key_free
TRACE: leave sign_key_free
TRACE: leave cli_pubkeyfail
TRACE: Methods (len 18): 'publickey,password'
TRACE: auth method 'publickey'
TRACE: auth method 'password'
TRACE: leave recv_msg_userauth_failure
TRACE: leave process_packet
TRACE: enter cli_sessionloop
TRACE: enter cli_auth_try
TRACE: enter cli_auth_pubkey
TRACE: leave cli_auth_pubkey-failure
TRACE: enter cli_auth_password
Password:

Any idea what is wrong ?