How do I fix: Verifying debugpy.listen() Function?

Step 1: Check that the debugpy.listen() function is using the correct host address. Verify that the hostname and port number match the SSH tunnel configuration.Step 2: Try using a different host address in the debugpy.listen() function to see if it resolves the issue.

Software⏱️ 3 min read📅 2026-06-15

How to Fix: Visual Studio Code and Debugpy remote debugging - "Client Authentication Failed" Error

Q: Best Solutions to Fix It Configuring SSH Tunnel Authentication?

Step 1: Ensure that the private key and passphrase are correctly configured in the .ssh/config file. Verify that the correct username and hostname are used in the ssh command.Step 2: Add the following line to the .ssh/config file: Host User IdentityFile Step 3: Restart the SSH service on the Windows

Debugpy remote debugging issue with Visual Studio Code and Oracle Linux server

Quick Answer: Ensure the SSH tunnel is established correctly and the IP address used in debugpy.listen() matches the one configured in the .ssh/config file.

📋 Table of Contents

💡 Why You Are Getting This Error
✅ Best Solutions to Fix It
✨ Wrapping Up

Visual Studio Code and Debugpy remote debugging with Python is not functioning as expected due to a 'Client Authentication Failed' error. This issue affects users who are trying to attach to a running Python script on an Oracle Linux server from a Windows 10 workstation.

The frustration of encountering this error can be overwhelming, especially when the goal is to efficiently debug and improve the performance of a remote application. In this guide, we will walk through the steps to troubleshoot and resolve the 'Client Authentication Failed' issue in Visual Studio Code and Debugpy.

💡 Why You Are Getting This Error

The primary reason for this error is that the SSH tunnel created from the Windows workstation to the Oracle Linux server does not include the necessary authentication configuration. The SSH client on the Windows machine may not be configured to use the correct private key or passphrase.
An alternative cause could be that the debugpy.listen() function is using an incorrect host address, which might result in a connection failure.

✅ Best Solutions to Fix It

Configuring SSH Tunnel Authentication

Step 1: Ensure that the private key and passphrase are correctly configured in the .ssh/config file. Verify that the correct username and hostname are used in the ssh command.
Step 2: Add the following line to the .ssh/config file: Host User IdentityFile
Step 3: Restart the SSH service on the Windows machine or restart the tunnel after making changes to the configuration.

Verifying debugpy.listen() Function

Step 1: Check that the debugpy.listen() function is using the correct host address. Verify that the hostname and port number match the SSH tunnel configuration.
Step 2: Try using a different host address in the debugpy.listen() function to see if it resolves the issue.

✨ Wrapping Up

To resolve the 'Client Authentication Failed' error in Visual Studio Code and Debugpy, ensure that the SSH tunnel is configured correctly with authentication. Verify that the debugpy.listen() function is using the correct host address. By following these steps, you should be able to successfully attach to your remote Python script and begin debugging.

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