Help with SFTP : error "Host key verification failed"

Hi All



I'm try to connect via SFTP to a supplier's server , but I receive the
error "Host key verification failed" ;

The supplier told me that "..doing connection tests with your user , the
problem described does not occur, there are no keys activated on the server
side .."

I tryed also to run "ssh-keygen -R [hostname|IP address]" , did not solved
the problem



This is the log that i collected



sftp -vvv -b /tmp/sftp/DFT_SFTPSRV_SFTP myuser@xxxxxxxxxxxxxxxx

OpenSSH_6.9p1, OpenSSL 1.0.2n 7 Dec 2017

debug1: Reading configuration data
/QOpenSys/QIBM/ProdData/SC1/OpenSSH/etc/ssh_config

debug2: ssh_connect: needpriv 0

debug1: Connecting to sftp.SFTPSRV.it [YYY.WW.HHH.ZZ] port 22.

debug1: Connection established.

debug1: key_load_public: No such file or directory

debug1: identity file /home/USER/.ssh/id_rsa type -1

debug1: key_load_public: No such file or directory

debug1: identity file /home/USER/.ssh/id_rsa-cert type -1

debug1: key_load_public: No such file or directory

debug1: identity file /home/USER/.ssh/id_dsa type -1

debug1: key_load_public: No such file or directory

debug1: identity file /home/USER/.ssh/id_dsa-cert type -1

debug1: key_load_public: No such file or directory

debug1: identity file /home/USER/.ssh/id_ecdsa type -1

debug1: key_load_public: No such file or directory

debug1: identity file /home/USER/.ssh/id_ecdsa-cert type -1

debug1: key_load_public: No such file or directory

debug1: identity file /home/USER/.ssh/id_ed25519 type -1

debug1: key_load_public: No such file or directory

debug1: identity file /home/USER/.ssh/id_ed25519-cert type -1

debug1: Enabling compatibility mode for protocol 2.0

debug1: Local version string SSH-2.0-OpenSSH_6.9

debug1: Remote protocol version 2.0, remote software version OpenSSH_8.0

debug1: match: OpenSSH_8.0 pat OpenSSH* compat 0x04000000

debug2: fd 3 setting O_NONBLOCK

debug1: Authenticating to sftp.SFTPSRV.it:22 as 'myuser'

debug1: SSH2_MSG_KEXINIT sent

debug1: SSH2_MSG_KEXINIT received

debug2: kex_parse_kexinit: curve25519-sha256@libssh.xxxxxxxxxx

debug2: kex_parse_kexinit: umac-64-etm@xxxxxxxxxxx,umac-128-zzzzzzzzzz

debug2: kex_parse_kexinit: none,zlib@xxxxxxxxxxx

debug2: kex_parse_kexinit: none,zlib@xxxxxxxxxxx

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: curve25519-sha256,curve25519-yyyyyyyy

debug2: kex_parse_kexinit: rsa-sha2-512,rsa-sha2-256,kkkkkkkk

debug2: kex_parse_kexinit: aes256-gcm@xxxxxxxxxxx,chacha20-xxxxxx

debug2: kex_parse_kexinit: aes256-gcm@openssh.jjjjj

debug2: kex_parse_kexinit: hmac-sha2-256-etm@xxxxxxxxxxx,hhhhh

debug2: kex_parse_kexinit: hmac-sha2-256-etm@openssh.iiiiii

debug2: kex_parse_kexinit: none,zlib@xxxxxxxxxxx

debug2: kex_parse_kexinit: none,zlib@xxxxxxxxxxx

debug2: kex_parse_kexinit:

debug2: kex_parse_kexinit:

debug2: kex_parse_kexinit: first_kex_follows 0

debug2: kex_parse_kexinit: reserved 0

debug1: kex: server->client chacha20-poly1305@xxxxxxxxxxx <implicit> none

debug1: kex: client->server chacha20-poly1305@xxxxxxxxxxx <implicit> none

debug1: expecting SSH2_MSG_KEX_ECDH_REPLY

debug1: Server host key: ecdsa-sha2-nistp256 SHA256:ddddddd

Host key verification failed.

Connection closed



Which could be the problem ?