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

In dem Bericht wird keine Quelldatei und kein Test genannt. Beginne damit, den SSH.NET-Authentifizierungsaustausch gegen den gemeldeten Serv-U_15.1.6.25-Server unter Verwendung des bereitgestellten OpenSSH-7.5/AIX-Kontexts zu reproduzieren, und ermittle anschließend, ob die Antwort vom Typ 100 korrekt verarbeitet wird; abgeschlossen ist die Aufgabe, wenn eine bestätigte Ursache sowie ein Regressionstest oder ein dokumentiertes Kompatibilitätsergebnis vorliegen.