STRSFTP revisited

Hello sages

Not long ago I've successfully created a batch script for downloading files
from
a certain SFTP Site using the QMGTOOLS/STRSFTP CMD.
It still runs fine.

However,
Trying the same method for another SFTP Site fails with a 'Connections
closed"
The log reads: (I have anonymized the name/address)

OpenSSH_8.0p1, OpenSSL 1.1.1k 25 Mar 2021
debug1: Reading configuration data
/QOpenSys/QIBM/ProdData/SC1/OpenSSH/etc/ssh_config
debug1: Connecting to ftp-ZZZZZ.com [35.191.40.60] port 22.
debug1: fd 3 clearing O_NONBLOCK
debug1: Connection established.
debug1: identity file /home/GAD/.ssh/id_rsa type -1
debug1: identity file /home/GAD/.ssh/id_rsa-cert type -1
debug1: identity file /home/GAD/.ssh/id_dsa type -1
debug1: identity file /home/GAD/.ssh/id_dsa-cert type -1
debug1: identity file /home/GAD/.ssh/id_ecdsa type -1
debug1: identity file /home/GAD/.ssh/id_ecdsa-cert type -1
debug1: identity file /home/GAD/.ssh/id_ed25519 type -1
debug1: identity file /home/GAD/.ssh/id_ed25519-cert type -1
debug1: identity file /home/GAD/.ssh/id_xmss type -1
debug1: identity file /home/GAD/.ssh/id_xmss-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_8.0
debug1: Remote protocol version 2.0, remote software version CrushFTPSSHD
debug1: no match: CrushFTPSSHD
debug1: Authenticating to ftp-ZZZZZZ.com:22 as 'userx'
debug1: SSH2_MSG_KEXINIT sent
Connection closed by 34.193.30.70 port 22
Connection closed

Looking at the log for the cooperative first SFTP Site I find:
....
debug1: Remote protocol version 2.0, remote software version prontosftp
debug1: no match: prontosftp
debug1: Authenticating to WorkingfineSftp.com:22 as '123156789'
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: algorithm: curve25519-sha256@xxxxxxxxxx
debug1: kex: host key algorithm: ssh-rsa
......

Both SFTP Sites require a user + password which I have omitted here for
obvious reasons

TIA

Gad