*** The server produces the following logs:

debug2: fd 3 setting O_NONBLOCK
debug3: privsep user:group 109:65534
debug1: permanently_set_uid: 109/65534
debug1: list_hostkey_types: ssh-rsa,ssh-dss
debug1: SSH2_MSG_KEXINIT sent
debug2: Network child is on pid 13449
debug3: preauth child monitor started
debug3: mm_request_receive entering

<<< ***** Sits here doing nothing for about five seconds...

debug1: SSH2_MSG_KEXINIT received
debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-rsa,ssh-dss
debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour128,arcfour256,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr

*** The client produces the following logs:

debug1: Remote protocol version 2.0, remote software version OpenSSH_4.3p2 Debian-8
debug1: match: OpenSSH_4.3p2 Debian-8 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_4.3p2 Debian-10
debug2: fd 3 setting O_NONBLOCK

<<< ***** Sits here doing nothing for about five seconds...

debug1: Miscellaneous failure
No credentials cache found

debug1: Miscellaneous failure
No credentials cache found

debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received