Troubleshooting steps
https://github.com/PowerShell/Win32-OpenSSH/wiki/Troubleshooting-Steps
1.Open x server like Vcxsrv
2. ENV setting
$ENV:PATH += ";C:\Windows\System32\OpenSSH"
$env:DISPLAY='localhost:0.0'
3. ssh -Y xxx@host

I cannot connect to the server. Without DISPLAY environment var, connection is no problem. I can also connect and forward x with other ssh client like putty or ssh in cygwin. I want to try this ssh because I found all the other ssh client on windows is slow in terms of x forwarding except for the embedded one in mobaxterm, which is a commercial software. I want to try whether this would be better.

error message:
CreateProcessW failed error:2
ssh_askpass: posix_spawn: No such file or directory

With -vvv option
OpenSSH_for_Windows_7.7p1, LibreSSL 2.6.5
debug1: Reading configuration data C:\Users\myuser/.ssh/config
debug3: Failed to open file:C:/ProgramData/ssh/ssh_config error:2
debug2: resolving "myhost.com" port 22
debug2: ssh_connect_direct: needpriv 0
debug1: Connecting to myhost.com [hostip] port 22.
debug1: Connection established.
debug3: Failed to open file:C:/Users/myuser/.ssh/id_rsa error:2
debug3: Failed to open file:C:/Users/myuser/.ssh/id_rsa.pub error:2
debug1: key_load_public: No such file or directory
debug1: identity file C:\Users\myuser/.ssh/id_rsa type -1
debug3: Failed to open file:C:/Users/myuser/.ssh/id_rsa-cert error:2
debug3: Failed to open file:C:/Users/myuser/.ssh/id_rsa-cert.pub error:2
debug1: key_load_public: No such file or directory
debug1: identity file C:\Users\myuser/.ssh/id_rsa-cert type -1
debug3: Failed to open file:C:/Users/myuser/.ssh/id_dsa error:2
debug3: Failed to open file:C:/Users/myuser/.ssh/id_dsa.pub error:2
debug1: key_load_public: No such file or directory
debug1: identity file C:\Users\myuser/.ssh/id_dsa type -1
debug3: Failed to open file:C:/Users/myuser/.ssh/id_dsa-cert error:2
debug3: Failed to open file:C:/Users/myuser/.ssh/id_dsa-cert.pub error:2
debug1: key_load_public: No such file or directory
debug1: identity file C:\Users\myuser/.ssh/id_dsa-cert type -1
debug3: Failed to open file:C:/Users/myuser/.ssh/id_ecdsa error:2
debug3: Failed to open file:C:/Users/myuser/.ssh/id_ecdsa.pub error:2
debug1: key_load_public: No such file or directory
debug1: identity file C:\Users\myuser/.ssh/id_ecdsa type -1
debug3: Failed to open file:C:/Users/myuser/.ssh/id_ecdsa-cert error:2
debug3: Failed to open file:C:/Users/myuser/.ssh/id_ecdsa-cert.pub error:2
debug1: key_load_public: No such file or directory
debug1: identity file C:\Users\myuser/.ssh/id_ecdsa-cert type -1
debug3: Failed to open file:C:/Users/myuser/.ssh/id_ed25519 error:2
debug3: Failed to open file:C:/Users/myuser/.ssh/id_ed25519.pub error:2
debug1: key_load_public: No such file or directory
debug1: identity file C:\Users\myuser/.ssh/id_ed25519 type -1
debug3: Failed to open file:C:/Users/myuser/.ssh/id_ed25519-cert error:2
debug3: Failed to open file:C:/Users/myuser/.ssh/id_ed25519-cert.pub error:2
debug1: key_load_public: No such file or directory
debug1: identity file C:\Users\myuser/.ssh/id_ed25519-cert type -1
debug3: Failed to open file:C:/Users/myuser/.ssh/id_xmss error:2
debug3: Failed to open file:C:/Users/myuser/.ssh/id_xmss.pub error:2
debug1: key_load_public: No such file or directory
debug1: identity file C:\Users\myuser/.ssh/id_xmss type -1
debug3: Failed to open file:C:/Users/myuser/.ssh/id_xmss-cert error:2
debug3: Failed to open file:C:/Users/myuser/.ssh/id_xmss-cert.pub error:2
debug1: key_load_public: No such file or directory
debug1: identity file C:\Users\myuser/.ssh/id_xmss-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_for_Windows_7.7
debug1: Remote protocol version 2.0, remote software version OpenSSH_7.4
debug1: match: OpenSSH_7.4 pat OpenSSH* compat 0x04000000
debug2: fd 3 setting O_NONBLOCK
debug1: Authenticating to myhost.com:22 as 'myuser'
debug3: hostkeys_foreach: reading file "C:\Users\myuser/.ssh/known_hosts"
debug3: record_hostkey: found key type RSA in file C:\Users\myuser/.ssh/known_hosts:7
debug3: load_hostkeys: loaded 1 keys from myhost.com
debug3: Failed to open file:C:/Users/myuser/.ssh/known_hosts2 error:2
debug3: Failed to open file:C:/ProgramData/ssh/ssh_known_hosts error:2
debug3: Failed to open file:C:/ProgramData/ssh/ssh_known_hosts2 error:2
debug3: order_hostkeyalgs: prefer hostkeyalgs: [email protected],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,[email protected],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: [email protected],rsa-sha2-512,rsa-sha2-256,ssh-rsa,[email protected],[email protected],[email protected],[email protected],ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,ssh-ed25519
debug2: ciphers ctos: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected]
debug2: ciphers stoc: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected]
debug2: MACs ctos: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none
debug2: compression stoc: none
debug2: languages ctos:
debug2: languages stoc:
debug2: first_kex_follows 0
debug2: reserved 0
debug2: peer server KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256,[email protected],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,diffie-hellman-group1-sha1
debug2: host key algorithms: ssh-rsa,rsa-sha2-512,rsa-sha2-256
debug2: ciphers ctos: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected],aes128-cbc,aes192-cbc,aes256-cbc,blowfish-cbc,cast128-cbc,3des-cbc
debug2: ciphers stoc: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected],aes128-cbc,aes192-cbc,aes256-cbc,blowfish-cbc,cast128-cbc,3des-cbc
debug2: MACs ctos: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,[email protected]
debug2: compression stoc: none,[email protected]
debug2: languages ctos:
debug2: languages stoc:
debug2: first_kex_follows 0
debug2: reserved 0
debug1: kex: algorithm: curve25519-sha256
debug1: kex: host key algorithm: rsa-sha2-512
debug1: kex: server->client cipher: [email protected] MAC: compression: none
debug1: kex: client->server cipher: [email protected] MAC: compression: none
debug3: send packet: type 30
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug3: receive packet: type 31
debug1: Server host key: ssh-rsa SHA256:btcMssrTCm0bJlzRJ88xQOsQ4o8smnsYG4EnE3m3/9M
debug3: hostkeys_foreach: reading file "C:\Users\myuser/.ssh/known_hosts"
debug3: record_hostkey: found key type RSA in file C:\Users\myuser/.ssh/known_hosts:7
debug3: load_hostkeys: loaded 1 keys from myhost.com
debug3: Failed to open file:C:/Users/myuser/.ssh/known_hosts2 error:2
debug3: Failed to open file:C:/ProgramData/ssh/ssh_known_hosts error:2
debug3: Failed to open file:C:/ProgramData/ssh/ssh_known_hosts2 error:2
debug3: hostkeys_foreach: reading file "C:\Users\myuser/.ssh/known_hosts"
debug3: record_hostkey: found key type RSA in file C:\Users\myuser/.ssh/known_hosts:8
debug3: load_hostkeys: loaded 1 keys from hostip
debug3: Failed to open file:C:/Users/myuser/.ssh/known_hosts2 error:2
debug3: Failed to open file:C:/ProgramData/ssh/ssh_known_hosts error:2
debug3: Failed to open file:C:/ProgramData/ssh/ssh_known_hosts2 error:2
debug1: Host 'myhost.com' is known and matches the RSA host key.
debug1: Found key in C:\Users\myuser/.ssh/known_hosts:7
debug3: send packet: type 21
debug2: set_newkeys: mode 1
debug1: rekey after 134217728 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 134217728 blocks
debug3: unable to connect to pipe \\.\pipe\openssh-ssh-agent, error: 2
debug1: pubkey_prepare: ssh_get_authentication_socket: No such file or directory
debug2: key: C:\Users\myuser/.ssh/id_rsa (0000000000000000)
debug2: key: C:\Users\myuser/.ssh/id_dsa (0000000000000000)
debug2: key: C:\Users\myuser/.ssh/id_ecdsa (0000000000000000)
debug2: key: C:\Users\myuser/.ssh/id_ed25519 (0000000000000000)
debug2: key: C:\Users\myuser/.ssh/id_xmss (0000000000000000)
debug3: send packet: type 5
debug3: receive packet: type 7
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info: server-sig-algs=<rsa-sha2-256,rsa-sha2-512>
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,gssapi-keyex,gssapi-with-mic,password,keyboard-interactive,hostbased
debug3: start over, passed a different list publickey,gssapi-keyex,gssapi-with-mic,password,keyboard-interactive,hostbased
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: C:\Users\myuser/.ssh/id_rsa
debug3: no such identity: C:\Users\myuser/.ssh/id_rsa: No such file or directory
debug1: Trying private key: C:\Users\myuser/.ssh/id_dsa
debug3: no such identity: C:\Users\myuser/.ssh/id_dsa: No such file or directory
debug1: Trying private key: C:\Users\myuser/.ssh/id_ecdsa
debug3: no such identity: C:\Users\myuser/.ssh/id_ecdsa: No such file or directory
debug1: Trying private key: C:\Users\myuser/.ssh/id_ed25519
debug3: no such identity: C:\Users\myuser/.ssh/id_ed25519: No such file or directory
debug1: Trying private key: C:\Users\myuser/.ssh/id_xmss
debug3: no such identity: C:\Users\myuser/.ssh/id_xmss: No such file or directory
debug2: we did not send a packet, disable method
debug3: authmethod_lookup keyboard-interactive
debug3: remaining preferred: password
debug3: authmethod_is_enabled keyboard-interactive
debug1: Next authentication method: keyboard-interactive
debug2: userauth_kbdint
debug3: send packet: type 50
debug2: we sent a keyboard-interactive packet, wait for reply
debug3: receive packet: type 60
debug2: input_userauth_info_req
debug2: input_userauth_info_req: num_prompts 1
debug3: failed to open file:C:/dev/tty error:3
debug1: read_passphrase: can't open /dev/tty: No such file or directory
debug3: spawning "/usr/X11R6/bin/ssh-askpass"
CreateProcessW failed error:2
ssh_askpass: posix_spawn: No such file or directory

Terminal issue? please go through wiki
https://github.com/PowerShell/Win32-OpenSSH/wiki/TTY-PTY-support-in-Windows-OpenSSH

Please answer the following

"OpenSSH for Windows" version
((Get-Item (Get-Command sshd).Source).VersionInfo.FileVersion)
I cannot run the command. But the version is shown in the debug info
OpenSSH_for_Windows_7.7p1, LibreSSL 2.6.5

Server OperatingSystem
((Get-ItemProperty "HKLM:\SOFTWARE\Microsoft\Windows nt\CurrentVersion\" -Name ProductName).ProductName)
CentOS7 or RHEL6

Client OperatingSystem
WIN10 1809

What is failing

Expected output

Actual output