can you post output with -vvvv flags, along with RouterOS ssh log with the problem.
ssh -vvv HOST
OpenSSH_5.8p2_hpn13v11 FreeBSD-20110503, OpenSSL 0.9.8q 2 Dec 2010
debug1: Reading configuration data /home/XXXXXX/.ssh/config
debug1: Reading configuration data /etc/ssh/ssh_config
debug2: ssh_connect: needpriv 0
debug1: Connecting to HOST [XXX.XXX.XXX.XXX] port 22.
debug2: fd 3 setting O_NONBLOCK
debug1: fd 3 clearing O_NONBLOCK
debug1: Connection established.
debug3: timeout: 9999 ms remain after connect
debug3: Incorrect RSA1 identifier
debug3: Could not load "/home/XXXXXX/.ssh/id_rsa" as a RSA1 public key
debug2: key_type_from_name: unknown key type '-----BEGIN'
debug3: key_read: missing keytype
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug2: key_type_from_name: unknown key type '-----END'
debug3: key_read: missing keytype
debug1: identity file /home/XXXXXX/.ssh/id_rsa type 1
debug1: identity file /home/XXXXXX/.ssh/id_rsa-cert type -1
debug3: Incorrect RSA1 identifier
debug3: Could not load "/home/XXXXXX/.ssh/id_dsa" as a RSA1 public key
debug2: key_type_from_name: unknown key type '-----BEGIN'
debug3: key_read: missing keytype
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug2: key_type_from_name: unknown key type '-----END'
debug3: key_read: missing keytype
debug1: identity file /home/XXXXXX/.ssh/id_dsa type 2
debug1: identity file /home/XXXXXX/.ssh/id_dsa-cert type -1
debug1: identity file /home/XXXXXX/.ssh/id_ecdsa type -1
debug1: identity file /home/XXXXXX/.ssh/id_ecdsa-cert type -1
debug1: Remote protocol version 2.0, remote software version ROSSSH
debug1: no match: ROSSSH
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_5.8p2_hpn13v11 FreeBSD-20110503
debug2: fd 3 setting O_NONBLOCK
debug3: ssh_load_hostkeys: loading entries for host "HOST" from file "/home/XXXXXX/.ssh/known_hosts"
debug3: ssh_load_hostkeys: found key type DSA in file /home/XXXXXX/.ssh/known_hosts:124
debug3: ssh_load_hostkeys: loaded 1 keys
debug3: order_hostkeyalgs: prefer hostkeyalgs:
ssh-dss-cert-v01@openssh.com,
ssh-dss-cert-v00@openssh.com,ssh-dss
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug2: kex_parse_kexinit: ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit:
ssh-dss-cert-v01@openssh.com,
ssh-dss-cert-v00@openssh.com,ssh-dss,
ecdsa-sha2-nistp256-cert-v01@openssh.com,
ecdsa-sha2-nistp384-cert-v01@openssh.com,
ecdsa-sha2-nistp521-cert-v01@openssh.com,
ssh-rsa-cert-v01@openssh.com,
ssh-rsa-cert-v00@openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,ssh-rsa
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,
rijndael-cbc@lysator.liu.se
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,
rijndael-cbc@lysator.liu.se
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,
umac-64@openssh.com,hmac-ripemd160,
hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,
umac-64@openssh.com,hmac-ripemd160,
hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,
zlib@openssh.com,zlib
debug2: kex_parse_kexinit: none,
zlib@openssh.com,zlib
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit: first_kex_follows 0
debug2: kex_parse_kexinit: reserved 0
debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-dss
debug2: kex_parse_kexinit: aes192-cbc,aes128-cbc,aes256-cbc,blowfish-cbc,3des-cbc
debug2: kex_parse_kexinit: aes192-cbc,aes128-cbc,aes256-cbc,blowfish-cbc,3des-cbc
debug2: kex_parse_kexinit: hmac-sha1,hmac-md5
debug2: kex_parse_kexinit: hmac-sha1,hmac-md5
debug2: kex_parse_kexinit: none
debug2: kex_parse_kexinit: none
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit: first_kex_follows 0
debug2: kex_parse_kexinit: reserved 0
debug2: mac_setup: found hmac-md5
debug1: kex: server->client aes128-cbc hmac-md5 none
debug2: mac_setup: found hmac-md5
debug1: kex: client->server aes128-cbc hmac-md5 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug2: dh_gen_key: priv key bits set: 133/256
debug2: bits set: 530/1024
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug1: Server host key: DSA bc:1a:0a:e6:38:3f:3c:2c:cf:3d:e1:00:f3:71:9e:e0
debug3: ssh_load_hostkeys: loading entries for host "HOST" from file "/home/XXXXXX/.ssh/known_hosts"
debug3: ssh_load_hostkeys: found key type DSA in file /home/XXXXXX/.ssh/known_hosts:124
debug3: ssh_load_hostkeys: loaded 1 keys
debug1: Host 'HOST' is known and matches the DSA host key.
debug1: Found key in /home/XXXXXX/.ssh/known_hosts:124
debug2: bits set: 512/1024
debug1: ssh_dss_verify: signature correct
debug2: kex_derive_keys
debug2: set_newkeys: mode 1
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug2: set_newkeys: mode 0
debug1: SSH2_MSG_NEWKEYS received
debug1: Roaming not allowed by server
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug2: key: /home/XXXXXX/.ssh/id_rsa (0x2882f0a0)
debug2: key: /home/XXXXXX/.ssh/id_dsa (0x2882f100)
debug2: key: /home/XXXXXX/.ssh/id_ecdsa (0x0)
debug1: Authentications that can continue: publickey,password
debug3: start over, passed a different list publickey,password
debug3: preferred publickey,keyboard-interactive,password
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Offering RSA public key: /home/XXXXXX/.ssh/id_rsa
debug3: send_pubkey_test
debug2: we sent a publickey packet, wait for reply
debug1: Authentications that can continue: publickey,password
debug1: Offering DSA public key: /home/XXXXXX/.ssh/id_dsa
debug3: send_pubkey_test
debug2: we sent a publickey packet, wait for reply
debug1: Server accepts key: pkalg ssh-dss blen 433
debug2: input_userauth_pk_ok: fp c1:9b:b9:8f:07:4c:77:e4:6b:6a:5b:e4:c8:2f:31:6c
debug3: sign_and_send_pubkey: DSA c1:9b:b9:8f:07:4c:77:e4:6b:6a:5b:e4:c8:2f:31:6c
debug1: read PEM private key done: type DSA
debug1: Authentication succeeded (publickey).
Authenticated to HOST ([XXX.XXX.XXX.XXX]:22).
debug1: Final hpn_buffer_size = 2097152
debug1: HPN Disabled: 0, HPN Buffer Size: 2097152
debug1: channel 0: new [client-session]
debug1: Enabled Dynamic Window Scaling
debug3: ssh_session2_open: channel_new: 0
debug2: channel 0: send open
debug1: Entering interactive session.
debug2: callback start
debug2: client_session2_setup: id 0
debug2: fd 3 setting TCP_NODELAY
debug3: packet_set_tos: set IP_TOS 0x10
debug2: channel 0: request pty-req confirm 1
debug2: channel 0: request shell confirm 1
debug2: callback done
debug2: channel 0: open confirm rwindow 2621440 rmax 262144
debug2: tcpwinsz: 66608 for connection: 3
debug2: tcpwinsz: 66608 for connection: 3
debug2: channel_input_status_confirm: type 99 id 0
debug2: PTY allocation request accepted on channel 0
debug2: tcpwinsz: 66608 for connection: 3
debug2: channel_input_status_confirm: type 99 id 0
debug2: shell request accepted on channel 0
debug2: tcpwinsz: 66608 for connection: 3
Then delay ~1 min and continue...
MMM MMM KKK TTTTTTTTTTT KKK
MMMM MMMM KKK TTTTTTTTTTT KKK
MMM MMMM MMM III KKK KKK RRRRRR OOOOOO TTT III KKK KKK
MMM Mdebug2: tcpwinsz: 66608 for connection: 3
debug2: tcpwinsz: 66608 for connection: 3
M MMM III KKKKK RRR RRR OOO OOO TTT III KKKKK
MMM MMM III KKK KKK RRRRRR OOO OOO TTT III KKK KKK
MMM MMM III KKK KKK RRR RRR OOOOOO TTT III KKK KKK
MikroTik RouterOS 5.20 (c) 19debug2: tcpwinsz: 66608 for connection: 3
debug2: tcpwinsz: 66608 for connection: 3
99-2012
http://www.mikrotik.com/
debug2: tcpwinsz: 66608 for connection: 3
And now waiting to infinity
-----------------------------------
ROS log:
15:42:03 ssh,info publickey accepted for user: XXXXXX
15:42:03 system,info,account user XXXXXX logged in from XXX.XXX.XXX.XXX via ssh