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Troubleshooting a connection to a workstation

SSH​

It is easiest to troubleshoot SSH connections using a terminal. Additionally, to display debugging information, we recommend running your SSH client with the flags -vvv.

Below are solutions to common issues with SSH connections to workstations.

  • You receive a message similar to bench-user@yellow-swordtail-vwk: Permission denied (publickey). Ensure you uploaded the correct public key to your account (see more) and you are using your SSH client with the corresponding private key.

  • You receive the message Too many authentication failures while attempting to connect to a workstation. This message may indicate that your SSH agent does not have the key for your workstation, or that your SSH agent cannot infer the appropriate key for your workstation because it has too many keys. Try removing the keys from your SSH agent and re-adding the key for your workstation to your SSH agent.

  • You receive an error about your SSH key, even though the key is correct and saved to the correct location. This could be the result of invalid permissions for your private key file. Run the following command to correct the permissions for your private key file, replacing {ssh-private-key-file} with the path to your private SSH key file.

    SSH key permissions command
    chmod 600 {ssh-private-key-file}

  • You see a message similar below when trying to connect:

    Warning message
    @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
    @    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @
    @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
    IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
    Someone could be eavesdropping on you right now (man-in-the-middle attack)!
    It is also possible that a host key has just been changed.

    This message is a warning about a potential security risk. Typically, this warning is due to a kink in our workstation provisioning system. This warning can be addressed by following the on-screen instructions that follow the above warning.

  • You are on Windows, and have an error related to OpenSSL. This may be because OpenSSL is not installed on your computer or because the OpenSSL executable is not on your system path. If OpenSSL is not installed on your computer, follow these instructions for installing OpenSSL. If OpenSSL is installed on your computer, follow these instructions for adding OpenSSL to your system path.

Remote backend for VS Code​

Below are solutions to common issues with connecting to workstations as remote backends for VS Code.

  • You are unable to use the Remote-SSH extension to execute a Jupyter notebook with a workstation. Sometimes VS Code fails to automatically identify kernels for executing Jupyter notebooks. We recommend using the button at the top-right of the Jupyter window within VS Code to explicitly select the kernel that you would like to use to execute Jupyter notebooks.
  • You are unable to connect to a workstation as a remote backend for a Jupyter notebook. We do not support this method for connecting to workstations because it is insecure. Instead, we recommend following the steps below to use a workstation to execute a Jupyter notebook.
    1. Follow these instructions to connect to a workstation via SSH from VS Code.
    2. Install the Jupyter VS Code extension for the remote workstation.
    3. Use VS Code to create or open a Jupyter notebook.
    4. If a pop-up opens with the title "Connecting over HTTP with a token may be an insecure connection ...", click "Yes".
    5. Use the button at the top-right of the Jupyter window within VS Code to select the kernel that you would like to use with your Jupyter notebook.

Additional help​

Additional help

For additional help, please contact us through our customer service portal.