Git authentication issues can be frustrating, especially when they interrupt your workflow. The “Git authentication failed” error typically occurs when Git cannot authenticate your credentials with the remote repository. This guide provides several methods to troubleshoot and resolve this common issue.

Common Causes of the Error

• Incorrect Credentials: Mistyped username or password.
• Expired or Revoked Tokens: OAuth tokens or SSH keys may expire or get revoked.
• Configuration Issues: Incorrect Git configuration settings.
• 2-Factor Authentication (2FA): Additional authentication steps not handled by Git.

Solutions to Fix “Git Authentication Failed”

1. Verify Your Credentials

Ensure that you are using the correct username and password. If you recently changed your password, update it in your Git configuration.

Re-enter Your Credentials:

git config --global --unset user.name
git config --global --unset user.email
git config --global user.name "your_username"
git config --global user.email "[email protected]"

2. Use a Personal Access Token (PAT)

Many platforms like GitHub no longer accept passwords for Git operations. Instead, they require a Personal Access Token (PAT).

Generate a PAT on GitHub:

• Go to your GitHub account settings.
• Navigate to “Developer settings” > “Personal access tokens.”
• Generate a new token with the required scopes (e.g., repo for repository access).

Use PAT for Git Operations:

When prompted for a password, use the PAT instead of your GitHub password.

3. Configure SSH Key Authentication

Using SSH keys is a secure way to authenticate Git operations without repeatedly entering your credentials.

Generate a New SSH Key:

ssh-keygen -t rsa -b 4096 -C "[email protected]"

Add the SSH Key to the SSH Agent:

eval "$(ssh-agent -s)"
ssh-add ~/.ssh/id_rsa

Add the SSH Key to Your GitHub Account: Copy the SSH key to your clipboard:

cat ~/.ssh/id_rsa.pub

Add it to your GitHub account under “Settings” > “SSH and GPG keys.”

Change the Remote URL to Use SSH:

git remote set-url origin [email protected]:username/repository.git

4. Update Stored Credentials

If you’re using a credential helper, update your stored credentials.

For macOS (using Keychain):

git credential-osxkeychain erase

For Windows (using Credential Manager):

git credential-manager erase

After clearing the credentials, Git will prompt you to enter them again during the next operation.

5. Check Your .netrc File

If you have a .netrc file for storing credentials, ensure it’s correctly configured.

Edit Your .netrc File:

nano ~/.netrc

Ensure it contains the correct credentials:

machine github.com
login your_username
password your_token

6. Disable Two-Factor Authentication (2FA)

If your platform uses 2FA, ensure that Git operations can handle it. If not, you might need to generate a PAT.

For GitHub:

Follow the steps to generate a PAT with appropriate scopes as mentioned earlier.

7. Update Git

Ensure you’re using the latest version of Git, as updates often include important security and functionality improvements.

Update Git on macOS:

brew upgrade git

Update Git on Windows:

Download and install the latest version from the official Git website.

8. Check Repository Permissions

Ensure that your user account has the necessary permissions to access the repository.

Verify Permissions:

Check the repository settings on the hosting platform (e.g., GitHub, GitLab) to ensure your user has the required access.

9. Check Internet Connectivity

Ensure that your network connection is stable and that there are no firewalls or proxies blocking Git connections.