input_userauth_error: bad message during authentication: type 100

I am trying to connect with a server using SSH. I have been struggling with this for a few days, Earlier it used to work but after some upgrade activity at OS[AIX] level may be SSH upgrade it stopped working.

Below is the error code which it shows:
input_userauth_error: bad message during authentication: type 100

I have generated ssh keys using ssh-keygen command
Generating public/private rsa key pair.
Enter file in which to save the key (/home/user/.ssh/id_rsa): ....

and I have shared the public key to place in the remote server.

For troubleshooting below is the code which I got with command ssh -vvv sftp user@remoteserver

OpenSSH_7.5p1, OpenSSL 1.0.2p 14 Aug 2018
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Failed dlopen: /usr/krb5/lib/libkrb5.a(libkrb5.a.so): Could not load module /usr/krb5/lib/libkrb5.a(libkrb5.a.so).
System error: No such file or directory

debug1: Error loading Kerberos, disabling Kerberos auth.
debug2: resolving "195.35.XXX.191" port 22
debug2: ssh_connect_direct: needpriv 0
debug1: Connecting to 195.35.XXX.191 [195.35.XXX.191] 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_7.5
debug1: Remote protocol version 2.0, remote software version Serv-U_15.1.6.25
debug1: no match: Serv-U_15.1.6.25
debug2: fd 3 setting O_NONBLOCK
debug1: Authenticating to 195.35.XXX.191:22 as 'user'
debug3: hostkeys_foreach: reading file "/home/user/.ssh/known_hosts"
debug3: record_hostkey: found key type RSA in file /home/user/.ssh/known_hosts:1
debug3: load_hostkeys: loaded 1 keys from 195.35.XXX.191
debug3: order_hostkeyalgs: prefer hostkeyalgs: ssh-rsa-cert-v01@openssh.com,rsa-sha2-512,rsa-sha2-256,ssh-rsa
debug3: send packet: type 20
debug1: SSH2_MSG_KEXINIT sent
debug3: receive packet: type 20
debug1: SSH2_MSG_KEXINIT received
debug2: local client KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256,curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha256,diffie-hellman-group14-sha1,ext-info-c
debug2: host key algorithms: ssh-rsa-cert-v01@openssh.com,rsa-sha2-512,rsa-sha2-256,ssh-rsa,ecdsa-sha2-nistp256-cert-v01@openssh.com,ecdsa-sha2-nistp384-cert-v01@openssh.com,ecdsa-sha2-nistp521-cert-v01@openssh.com,ssh-ed25519-cert-v01@openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,ssh-ed25519
debug2: ciphers ctos: aes128-ctr,aes192-ctr,aes256-ctr,chacha20-poly1305@openssh.com,aes128-gcm@openssh.com,aes256-gcm@openssh.com,aes128-cbc,aes192-cbc,aes256-cbc
debug2: ciphers stoc: aes128-ctr,aes192-ctr,aes256-ctr,chacha20-poly1305@openssh.com,aes128-gcm@openssh.com,aes256-gcm@openssh.com,aes128-cbc,aes192-cbc,aes256-cbc
debug2: MACs ctos: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,zlib@openssh.com,zlib
debug2: compression stoc: none,zlib@openssh.com,zlib
debug2: languages ctos:
debug2: languages stoc:
debug2: first_kex_follows 0
debug2: reserved 0
debug2: peer server KEXINIT proposal
debug2: KEX algorithms: ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: host key algorithms: ssh-rsa
debug2: ciphers ctos: aes128-cbc,rijndael128-cbc,3des-cbc,blowfish-cbc,aes192-cbc,rijndael192-cbc,aes256-cbc,rijndael256-cbc,rijndael-cbc@lysator.liu.se,cast128-cbc,rijndael-cbc@lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr
debug2: ciphers stoc: aes128-cbc,rijndael128-cbc,3des-cbc,blowfish-cbc,aes192-cbc,rijndael192-cbc,aes256-cbc,rijndael256-cbc,rijndael-cbc@lysator.liu.se,cast128-cbc,rijndael-cbc@lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr
debug2: MACs ctos: hmac-md5,hmac-sha1,hmac-sha1-96,hmac-sha2-256,hmac-sha2-256-96,hmac-sha2-512,hmac-sha2-512-96
debug2: MACs stoc: hmac-md5,hmac-sha1,hmac-sha1-96,hmac-sha2-256,hmac-sha2-256-96,hmac-sha2-512,hmac-sha2-512-96
debug2: compression ctos: zlib,none
debug2: compression stoc: zlib,none
debug2: languages ctos:
debug2: languages stoc:
debug2: first_kex_follows 0
debug2: reserved 0
debug1: kex: algorithm: ecdh-sha2-nistp256
debug1: kex: host key algorithm: ssh-rsa
debug1: kex: server->client cipher: aes128-ctr MAC: hmac-sha2-256 compression: none
debug1: kex: client->server cipher: aes128-ctr MAC: hmac-sha2-256 compression: none
debug3: send packet: type 30
debug1: sending SSH2_MSG_KEX_ECDH_INIT
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug3: receive packet: type 31
debug1: Server host key: ssh-rsa SHA256:U7gTHqAEWWcc9s4RaafFus7Ijsdvqbd/3IS8Juih3ys
debug3: hostkeys_foreach: reading file "/home/user/.ssh/known_hosts"
debug3: record_hostkey: found key type RSA in file /home/user/.ssh/known_hosts:1
debug3: load_hostkeys: loaded 1 keys from 195.35.XXX.191
debug1: Host '195.35.XXX.191' is known and matches the RSA host key.
debug1: Found key in /home/user/.ssh/known_hosts:1
debug3: send packet: type 21
debug2: set_newkeys: mode 1
debug1: rekey after 4294967296 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug3: receive packet: type 21
debug1: SSH2_MSG_NEWKEYS received
debug2: set_newkeys: mode 0
debug1: rekey after 4294967296 blocks
debug2: key: /home/user/.ssh/id_rsa (0)
debug2: key: /home/user/.ssh/id_dsa (0)
debug2: key: /home/user/.ssh/id_ecdsa (0)
debug2: key: /home/user/.ssh/id_ed25519 (0)
debug3: send packet: type 5
debug3: receive packet: type 6
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug3: send packet: type 50
debug3: receive packet: type 51
debug1: Authentications that can continue: publickey
debug3: start over, passed a different list publickey
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: Trying private key: /home/user/.ssh/id_rsa
debug3: sign_and_send_pubkey: RSA SHA256:atNggY8MW6O2BP3wlJsqTqkmSpQ4ggObtvJ/UOjFswA
debug3: send packet: type 106
debug1: Sent ALLOW_PKCS12_KEYSTORE_CLIENT_FLAG packet
debug3: send packet: type 50
debug2: we sent a publickey packet, wait for reply
debug3: receive packet: type 100
input_userauth_error: bad message during authentication: type 100
Connection closed

Kindly advice on this

Nel report non vengono indicati né un file sorgente né un test. Inizia riproducendo lo scambio di autenticazione di SSH.NET con il server Serv-U_15.1.6.25 segnalato, utilizzando il contesto OpenSSH 7.5/AIX fornito, quindi identifica se la risposta di tipo 100 viene gestita correttamente; il lavoro è completato quando sono disponibili una causa confermata e un test di regressione oppure un esito di compatibilità documentato.