Why I cannot Remote SSH to ubuntu 22.04 from Safous?

This caused by default key type has been changed since OpenSSH 8.8 specification. Ubuntu 22.04 bundles with OpenSSH 8.9, while ssh-rsa (the most used key type) has been disabled since OpenSSH 8.8. 
Detail of OpesnSSH release can be found in here (https://www.openssh.com/txt/release-8.8)

Currently Safous ZTNA remote access for SSH still using the old key type (ssh-rsa), in order to do workaround for this issue, you can follow this steps:

  1. Access to the remote target of Ubuntu 22.04 server via console or any other method that you have
  2. Run this command to edit SSH service daemon configuration (or you could use your favorite text editor application other then Vim )
    sudo vi /etc/ssh/sshd_config
  3. Add these parameter inside of that configuration file
    HostkeyAlgorithms ssh-rsa
    PubkeyAcceptedAlgorithms +ssh-rsa
  4. Save it
  5. Restart the SSH service daemon
    sudo systemctl restart sshd
  6. If everything are going smoothly, then you can try to access again from Safous to remote access SSH to Ubuntu 22.04