SSH pubkey authentication fails while keys accepted, password auth works

SSH pubkey authentication fails while keys accepted, password auth works on the same machine without any changes

"OpenSSH for Windows" version

Get-Command 'C:\Program Files\OpenSSH\sshd.exe'

CommandType     Name                                               Version    Source
-----------     ----                                               -------    ------
Application     sshd.exe                                           8.1.0.0    C:\Program Files\OpenSSH\sshd.exe

Server OperatingSystem

((Get-ItemProperty "HKLM:\SOFTWARE\Microsoft\Windows nt\CurrentVersion\" -Name ProductName).ProductName)
Windows 10 Enterprise LTSC 2019

Client OperatingSystem
Linux

What is failing
I am able to logon via ssh on a Window 10 Domain member using password authentication.
However when I try to logon with the same account on the same machine using public key authentication it fails. The log files tells that the key is accepted.

Here is the relevant logfile snipplet:

6172 2020-07-02 10:50:25.727 Accepted publickey for administrator@dom from xxx.xxx.100.114 port 54726 ssh2: RSA SHA256:LPnAPE9RZjWDJa9fPueSe63Jo1InF9D+uxtIxKr/wEI
6172 2020-07-02 10:50:25.727 debug1: monitor_child_preauth: administrator@dom has been authenticated by privileged process
6172 2020-07-02 10:50:25.743 debug1: auth_activate_options: setting new authentication options [preauth]
6172 2020-07-02 10:50:25.743 debug1: monitor_read_log: child log fd closed
6172 2020-07-02 10:50:25.774 error: lookup_principal_name: User principal name lookup failed for user 'dom\\administrator@dom' (explicit: 1317, implicit: 1317)
6172 2020-07-02 10:50:25.774 debug1: generate_s4u_user_token: LsaLogonUser() failed. User 'dom\\administrator@dom' Status: 0x80090303 SubStatus 0.
6172 2020-07-02 10:50:25.837 error: lookup_principal_name: User principal name lookup failed for user 'dom\\administrator@dom' (explicit: 1317, implicit: 1317)
6172 2020-07-02 10:50:25.837 debug1: generate_s4u_user_token: LsaLogonUser() failed. User 'dom\\administrator@dom' Status: 0x80090303 SubStatus 0.
6172 2020-07-02 10:50:25.837 error: get_user_token - unable to generate token on 2nd attempt for user dom\\administrator@dom
6172 2020-07-02 10:50:25.837 error: unable to get security token for user dom\\administrator@dom
6172 2020-07-02 10:50:25.837 fatal: fork of unprivileged child failed
6172 2020-07-02 10:50:25.837 debug1: do_cleanup

I'm trying to logon from a Linux machine with
ssh -i private-ssh-key -l administrator@dom xxx.xxx.100.90

Expected output
Working ssh shell on Windows 10 Client

Microsoft Windows [Version 10.0.17763.1282]                         
(c) 2018 Microsoft Corporation. All rights reserved.                

dom\administrator@Win10Client C:\Users\administrator@dom>

Actual output

client_loop: send disconnect: Broken pipe

sshd_config

# This is the sshd server system-wide configuration file.  See
# sshd_config(5) for more information.

# The strategy used for options in the default sshd_config shipped with
# OpenSSH is to specify options with their default value where
# possible, but leave them commented.  Uncommented options override the
# default value.

#Port 22
#AddressFamily any
#ListenAddress 0.0.0.0
#ListenAddress ::

#HostKey __PROGRAMDATA__/ssh/ssh_host_rsa_key
#HostKey __PROGRAMDATA__/ssh/ssh_host_dsa_key
#HostKey __PROGRAMDATA__/ssh/ssh_host_ecdsa_key
#HostKey __PROGRAMDATA__/ssh/ssh_host_ed25519_key

# Ciphers and keying
#RekeyLimit default none

# Logging to ETW is default
#SyslogFacility AUTH
#LogLevel INFO 
LogLevel DEBUG
# Logging to FILE
SyslogFacility LOCAL0



# Authentication:

#LoginGraceTime 2m
#PermitRootLogin prohibit-password
#StrictModes yes
#MaxAuthTries 6
#MaxSessions 10

#PubkeyAuthentication yes

# The default is to check both .ssh/authorized_keys and .ssh/authorized_keys2
# but this is overridden so installations will only check .ssh/authorized_keys
AuthorizedKeysFile	.ssh/authorized_keys

#AuthorizedPrincipalsFile none

# For this to work you will also need host keys in %programData%/ssh/ssh_known_hosts
#HostbasedAuthentication no
# Change to yes if you don't trust ~/.ssh/known_hosts for
# HostbasedAuthentication
#IgnoreUserKnownHosts no
# Don't read the user's ~/.rhosts and ~/.shosts files
#IgnoreRhosts yes




# To disable tunneled clear text passwords, change to no here!
#PasswordAuthentication yes
#PermitEmptyPasswords no

#AllowAgentForwarding yes
#AllowTcpForwarding yes
#GatewayPorts no
#PermitTTY yes
#PrintMotd yes
#PrintLastLog yes
#TCPKeepAlive yes
#UseLogin no
#PermitUserEnvironment no
#ClientAliveInterval 0
#ClientAliveCountMax 3
#UseDNS no
#PidFile /var/run/sshd.pid
#MaxStartups 10:30:100
#PermitTunnel no
#ChrootDirectory none
#VersionAddendum none

# no default banner path
#Banner none

# override default of no subsystems
Subsystem	sftp	sftp-server.exe

# Example of overriding settings on a per-user basis
#Match User anoncvs
#	AllowTcpForwarding no
#	PermitTTY no
#	ForceCommand cvs server

#Match Group administrators
#       AuthorizedKeysFile __PROGRAMDATA__/ssh/administrators_authorized_keys

Password based authentication sshd.log

1680 2020-07-02 10:48:44.875 debug1: Bind to port 22 on ::.
1680 2020-07-02 10:48:44.875 Server listening on :: port 22.
1680 2020-07-02 10:48:44.875 debug1: Bind to port 22 on 0.0.0.0.
1680 2020-07-02 10:48:44.875 Server listening on 0.0.0.0 port 22.
3528 2020-07-02 10:48:45.828 debug1: inetd sockets after dupping: 4, 4
3528 2020-07-02 10:48:45.828 Connection from xxx.xxx.100.114 port 45414 on xxx.xxx.100.90 port 22
3528 2020-07-02 10:48:45.828 debug1: Local version string SSH-2.0-OpenSSH_for_Windows_8.1
3528 2020-07-02 10:48:45.828 error: kex_exchange_identification: Connection closed by remote host
6644 2020-07-02 10:49:02.396 debug1: inetd sockets after dupping: 4, 4
6644 2020-07-02 10:49:02.396 Connection from xxx.xxx.100.114 port 47512 on xxx.xxx.100.90 port 22
6644 2020-07-02 10:49:02.396 debug1: Local version string SSH-2.0-OpenSSH_for_Windows_8.1
6644 2020-07-02 10:49:02.396 debug1: Remote protocol version 2.0, remote software version OpenSSH_8.3
6644 2020-07-02 10:49:02.396 debug1: match: OpenSSH_8.3 pat OpenSSH* compat 0x04000000
6644 2020-07-02 10:49:02.427 debug1: list_hostkey_types: rsa-sha2-512,rsa-sha2-256,ssh-rsa,ecdsa-sha2-nistp256,ssh-ed25519 [preauth]
6644 2020-07-02 10:49:02.427 debug1: SSH2_MSG_KEXINIT sent [preauth]
6644 2020-07-02 10:49:02.427 debug1: SSH2_MSG_KEXINIT received [preauth]
6644 2020-07-02 10:49:02.427 debug1: kex: algorithm: curve25519-sha256 [preauth]
6644 2020-07-02 10:49:02.427 debug1: kex: host key algorithm: ecdsa-sha2-nistp256 [preauth]
6644 2020-07-02 10:49:02.427 debug1: kex: client->server cipher: chacha20-poly1305@openssh.com MAC: <implicit> compression: none [preauth]
6644 2020-07-02 10:49:02.427 debug1: kex: server->client cipher: chacha20-poly1305@openssh.com MAC: <implicit> compression: none [preauth]
6644 2020-07-02 10:49:02.427 debug1: expecting SSH2_MSG_KEX_ECDH_INIT [preauth]
6644 2020-07-02 10:49:02.442 debug1: rekey out after 134217728 blocks [preauth]
6644 2020-07-02 10:49:02.442 debug1: SSH2_MSG_NEWKEYS sent [preauth]
6644 2020-07-02 10:49:02.442 debug1: Sending SSH2_MSG_EXT_INFO [preauth]
6644 2020-07-02 10:49:02.442 debug1: expecting SSH2_MSG_NEWKEYS [preauth]
6644 2020-07-02 10:49:02.450 debug1: SSH2_MSG_NEWKEYS received [preauth]
6644 2020-07-02 10:49:02.450 debug1: rekey in after 134217728 blocks [preauth]
6644 2020-07-02 10:49:02.450 debug1: KEX done [preauth]
6644 2020-07-02 10:49:02.504 debug1: userauth-request for user administrator@dom service ssh-connection method none [preauth]
6644 2020-07-02 10:49:02.504 debug1: attempt 0 failures 0 [preauth]
6644 2020-07-02 10:49:02.520 debug1: userauth-request for user administrator@dom service ssh-connection method keyboard-interactive [preauth]
6644 2020-07-02 10:49:02.520 debug1: attempt 1 failures 0 [preauth]
6644 2020-07-02 10:49:02.520 debug1: keyboard-interactive devs  [preauth]
6644 2020-07-02 10:49:02.520 debug1: auth2_challenge: user=administrator@dom devs= [preauth]
6644 2020-07-02 10:49:02.520 debug1: kbdint_alloc: devices '' [preauth]
6644 2020-07-02 10:49:06.753 debug1: userauth-request for user administrator@dom service ssh-connection method password [preauth]
6644 2020-07-02 10:49:06.753 debug1: attempt 2 failures 1 [preauth]
6644 2020-07-02 10:49:06.800 error: lookup_principal_name: User principal name lookup failed for user 'dom\\administrator@dom' (explicit: 1317, implicit: 1317)
6644 2020-07-02 10:49:06.894 Accepted password for administrator@dom from xxx.xxx..100.114 port 47512 ssh2
6644 2020-07-02 10:49:06.894 debug1: monitor_child_preauth: administrator@dom has been authenticated by privileged process
6644 2020-07-02 10:49:07.003 debug1: monitor_read_log: child log fd closed
6644 2020-07-02 10:49:07.050 User child is on pid 1684
1684 2020-07-02 10:49:07.081 debug1: rekey in after 134217728 blocks
1684 2020-07-02 10:49:07.081 debug1: rekey out after 134217728 blocks
1684 2020-07-02 10:49:07.081 debug1: ssh_packet_set_postauth: called
1684 2020-07-02 10:49:07.081 debug1: active: key options: agent-forwarding port-forwarding pty user-rc x11-forwarding
1684 2020-07-02 10:49:07.081 debug1: Entering interactive session for SSH2.
1684 2020-07-02 10:49:07.081 debug1: server_init_dispatch
1684 2020-07-02 10:49:07.081 debug1: server_input_channel_open: ctype session rchan 0 win 1048576 max 16384
1684 2020-07-02 10:49:07.081 debug1: input_session_request
1684 2020-07-02 10:49:07.081 debug1: channel 0: new [server-session]
1684 2020-07-02 10:49:07.081 debug1: session_new: session 0
1684 2020-07-02 10:49:07.081 debug1: session_open: channel 0
1684 2020-07-02 10:49:07.081 debug1: session_open: session 0: link with channel 0
1684 2020-07-02 10:49:07.081 debug1: server_input_channel_open: confirm session
1684 2020-07-02 10:49:07.081 debug1: server_input_global_request: rtype no-more-sessions@openssh.com want_reply 0
1684 2020-07-02 10:49:07.081 debug1: server_input_channel_req: channel 0 request pty-req reply 1
1684 2020-07-02 10:49:07.081 debug1: session_by_channel: session 0 channel 0
1684 2020-07-02 10:49:07.081 debug1: session_input_channel_req: session 0 req pty-req
1684 2020-07-02 10:49:07.081 debug1: Allocating pty.
1684 2020-07-02 10:49:07.097 debug1: session_pty_req: session 0 alloc windows-pty
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 1 (0x1)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 2 (0x2)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 3 (0x3)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 4 (0x4)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 5 (0x5)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 6 (0x6)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 7 (0x7)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 8 (0x8)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 9 (0x9)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 10 (0xa)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 12 (0xc)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 13 (0xd)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 14 (0xe)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 18 (0x12)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 30 (0x1e)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 31 (0x1f)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 32 (0x20)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 33 (0x21)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 34 (0x22)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 35 (0x23)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 36 (0x24)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 37 (0x25)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 38 (0x26)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 39 (0x27)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 40 (0x28)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 41 (0x29)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 42 (0x2a)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 50 (0x32)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 51 (0x33)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 52 (0x34)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 53 (0x35)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 54 (0x36)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 55 (0x37)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 56 (0x38)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 57 (0x39)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 58 (0x3a)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 59 (0x3b)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 60 (0x3c)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 61 (0x3d)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 62 (0x3e)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 70 (0x46)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 71 (0x47)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 72 (0x48)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 73 (0x49)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 74 (0x4a)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 75 (0x4b)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 90 (0x5a)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 91 (0x5b)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 92 (0x5c)
1684 2020-07-02 10:49:07.097 debug1: Ignoring unsupported tty mode opcode 93 (0x5d)
1684 2020-07-02 10:49:07.097 debug1: server_input_channel_req: channel 0 request shell reply 1
1684 2020-07-02 10:49:07.097 debug1: session_by_channel: session 0 channel 0
1684 2020-07-02 10:49:07.097 debug1: session_input_channel_req: session 0 req shell
1684 2020-07-02 10:49:07.097 Starting session: shell on windows-pty for dom\\administrator from xxx.xxx.100.114 port 47512 id 0
1684 2020-07-02 10:49:09.091 debug1: Received SIGCHLD.
1684 2020-07-02 10:49:09.091 debug1: session_by_pid: pid 1656
1684 2020-07-02 10:49:09.091 debug1: session_exit_message: session 0 channel 0 pid 1656
1684 2020-07-02 10:49:09.091 debug1: session_exit_message: release channel 0
1684 2020-07-02 10:49:09.091 debug1: session_by_channel: session 0 channel 0
1684 2020-07-02 10:49:09.091 debug1: session_close_by_channel: channel 0 child 0
1684 2020-07-02 10:49:09.091 Close session: user dom\\administrator from xxx.xxx.100.114 port 47512 id 0
1684 2020-07-02 10:49:09.091 debug1: channel 0: free: server-session, nchannels 1
1684 2020-07-02 10:49:09.107 Received disconnect from xxx.xxx.100.114 port 47512:11: disconnected by user
1684 2020-07-02 10:49:09.107 Disconnected from xxx.xxx.100.114 port 47512
1684 2020-07-02 10:49:09.107 debug1: do_cleanup
6644 2020-07-02 10:49:09.107 debug1: do_cleanup

public key based authentication sshd.log

5408 2020-07-02 10:50:17.549 debug1: Bind to port 22 on ::.
5408 2020-07-02 10:50:17.549 Server listening on :: port 22.
5408 2020-07-02 10:50:17.549 debug1: Bind to port 22 on 0.0.0.0.
5408 2020-07-02 10:50:17.549 Server listening on 0.0.0.0 port 22.
6172 2020-07-02 10:50:25.587 debug1: inetd sockets after dupping: 4, 4
6172 2020-07-02 10:50:25.587 Connection from xxx.xxx.100.114 port 54726 on xxx.xxx.100.90 port 22
6172 2020-07-02 10:50:25.587 debug1: Local version string SSH-2.0-OpenSSH_for_Windows_8.1
6172 2020-07-02 10:50:25.587 debug1: Remote protocol version 2.0, remote software version OpenSSH_8.3
6172 2020-07-02 10:50:25.587 debug1: match: OpenSSH_8.3 pat OpenSSH* compat 0x04000000
6172 2020-07-02 10:50:25.618 debug1: list_hostkey_types: rsa-sha2-512,rsa-sha2-256,ssh-rsa,ecdsa-sha2-nistp256,ssh-ed25519 [preauth]
6172 2020-07-02 10:50:25.618 debug1: SSH2_MSG_KEXINIT sent [preauth]
6172 2020-07-02 10:50:25.618 debug1: SSH2_MSG_KEXINIT received [preauth]
6172 2020-07-02 10:50:25.618 debug1: kex: algorithm: curve25519-sha256 [preauth]
6172 2020-07-02 10:50:25.618 debug1: kex: host key algorithm: ecdsa-sha2-nistp256 [preauth]
6172 2020-07-02 10:50:25.618 debug1: kex: client->server cipher: chacha20-poly1305@openssh.com MAC: <implicit> compression: none [preauth]
6172 2020-07-02 10:50:25.618 debug1: kex: server->client cipher: chacha20-poly1305@openssh.com MAC: <implicit> compression: none [preauth]
6172 2020-07-02 10:50:25.618 debug1: expecting SSH2_MSG_KEX_ECDH_INIT [preauth]
6172 2020-07-02 10:50:25.634 debug1: rekey out after 134217728 blocks [preauth]
6172 2020-07-02 10:50:25.634 debug1: SSH2_MSG_NEWKEYS sent [preauth]
6172 2020-07-02 10:50:25.634 debug1: Sending SSH2_MSG_EXT_INFO [preauth]
6172 2020-07-02 10:50:25.634 debug1: expecting SSH2_MSG_NEWKEYS [preauth]
6172 2020-07-02 10:50:25.634 debug1: SSH2_MSG_NEWKEYS received [preauth]
6172 2020-07-02 10:50:25.634 debug1: rekey in after 134217728 blocks [preauth]
6172 2020-07-02 10:50:25.634 debug1: KEX done [preauth]
6172 2020-07-02 10:50:25.696 debug1: userauth-request for user administrator@dom service ssh-connection method none [preauth]
6172 2020-07-02 10:50:25.696 debug1: attempt 0 failures 0 [preauth]
6172 2020-07-02 10:50:25.712 debug1: userauth-request for user administrator@dom service ssh-connection method publickey [preauth]
6172 2020-07-02 10:50:25.712 debug1: attempt 1 failures 0 [preauth]
6172 2020-07-02 10:50:25.712 debug1: userauth_pubkey: test pkalg rsa-sha2-512 pkblob RSA SHA256:LPnAPE9RZjWDJa9fPueSe63Jo1InF9D+uxtIxKr/wEI [preauth]
6172 2020-07-02 10:50:25.712 debug1: trying public key file C:\\Users\\administrator@dom\\.ssh/authorized_keys
6172 2020-07-02 10:50:25.712 debug1: C:\\Users\\administrator@dom\\.ssh/authorized_keys:1: matching key found: RSA SHA256:LPnAPE9RZjWDJa9fPueSe63Jo1InF9D+uxtIxKr/wEI
6172 2020-07-02 10:50:25.712 debug1: C:\\Users\\administrator@dom\\.ssh/authorized_keys:1: key options: agent-forwarding port-forwarding pty user-rc x11-forwarding
6172 2020-07-02 10:50:25.712 Accepted key RSA SHA256:LPnAPE9RZjWDJa9fPueSe63Jo1InF9D+uxtIxKr/wEI found at C:\\Users\\administrator@dom\\.ssh/authorized_keys:1
6172 2020-07-02 10:50:25.727 Postponed publickey for administrator@dom from xxx.xxx.100.114 port 54726 ssh2 [preauth]
6172 2020-07-02 10:50:25.727 debug1: userauth-request for user administrator@dom service ssh-connection method publickey [preauth]
6172 2020-07-02 10:50:25.727 debug1: attempt 2 failures 0 [preauth]
6172 2020-07-02 10:50:25.727 debug1: trying public key file C:\\Users\\administrator@dom\\.ssh/authorized_keys
6172 2020-07-02 10:50:25.727 debug1: C:\\Users\\administrator@dom\\.ssh/authorized_keys:1: matching key found: RSA SHA256:LPnAPE9RZjWDJa9fPueSe63Jo1InF9D+uxtIxKr/wEI
6172 2020-07-02 10:50:25.727 debug1: C:\\Users\\administrator@dom\\.ssh/authorized_keys:1: key options: agent-forwarding port-forwarding pty user-rc x11-forwarding
6172 2020-07-02 10:50:25.727 Accepted key RSA SHA256:LPnAPE9RZjWDJa9fPueSe63Jo1InF9D+uxtIxKr/wEI found at C:\\Users\\administrator@dom\\.ssh/authorized_keys:1
6172 2020-07-02 10:50:25.727 debug1: auth_activate_options: setting new authentication options
6172 2020-07-02 10:50:25.727 Accepted publickey for administrator@dom from xxx.xxx.100.114 port 54726 ssh2: RSA SHA256:LPnAPE9RZjWDJa9fPueSe63Jo1InF9D+uxtIxKr/wEI
6172 2020-07-02 10:50:25.727 debug1: monitor_child_preauth: administrator@dom has been authenticated by privileged process
6172 2020-07-02 10:50:25.743 debug1: auth_activate_options: setting new authentication options [preauth]
6172 2020-07-02 10:50:25.743 debug1: monitor_read_log: child log fd closed
6172 2020-07-02 10:50:25.774 error: lookup_principal_name: User principal name lookup failed for user 'dom\\administrator@dom' (explicit: 1317, implicit: 1317)
6172 2020-07-02 10:50:25.774 debug1: generate_s4u_user_token: LsaLogonUser() failed. User 'dom\\administrator@dom' Status: 0x80090303 SubStatus 0.
6172 2020-07-02 10:50:25.837 error: lookup_principal_name: User principal name lookup failed for user 'dom\\administrator@dom' (explicit: 1317, implicit: 1317)
6172 2020-07-02 10:50:25.837 debug1: generate_s4u_user_token: LsaLogonUser() failed. User 'dom\\administrator@dom' Status: 0x80090303 SubStatus 0.
6172 2020-07-02 10:50:25.837 error: get_user_token - unable to generate token on 2nd attempt for user dom\\administrator@dom
6172 2020-07-02 10:50:25.837 error: unable to get security token for user dom\\administrator@dom
6172 2020-07-02 10:50:25.837 fatal: fork of unprivileged child failed
6172 2020-07-02 10:50:25.837 debug1: do_cleanup

Start by reproducing the failure with the supplied Linux ssh command and compare the public-key and password-authentication log excerpts. Trace the reported principal lookup and token-generation failures; done means public-key login reaches a working Windows shell without the token or child-process errors.