E401 Unable to authenticate, your authentication token seems to be invalid | bobbyhadz (2024)

# Table of Contents

1. E401 Unable to authenticate, your authentication token seems to be invalid
2. Remove your package-lock.json file and reinstall your dependencies
3. Try to set your NPM registry correctly
4. Solving the error when using Azure
5. Check if your package.json file contains a supported Node.js version

# E401 Unable to authenticate, your authentication token seems to be invalid

The NPM 401 error "Unable to authenticate, your authentication token seems tobe invalid" occurs when you've specified incorrect credentials in your .npmrcfile.

To solve the error, make sure the contents of your .npmrc file are correct,delete your package-lock.json and reinstall your dependencies.

Here is the complete error message:

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npm ERR! code E401npm ERR! Unable to authenticate, your authentication token seems to be invalid.npm ERR! To correct this please try logging in again with:npm ERR! npm login

The first thing you should check is if your .npmrc file contains private repocredentials.

• On macOS and Linux, the file is located at ~/.npmrc.

• On Windows, the file is located at C:\Users\%username%\.npmrc.

For example, if you are on macOS or Linux, you can open the file in gedit,nano or vim and check if it contains private repo credentials that wouldprevent you from running npm install.

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# with Geditsudo gedit ~/.npmrc# or with Nanosudo nano ~/.npmrc

You can also try to temporarily rename the ~/.npmrc file and see if the issueis resolved.

On macOS and Linux, run the following command to create a copy of the file.

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cp ~/.npmrc ~/.npmrc_copy

And then remove the original file by running the following command.

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rm -f ~/.npmrc

If you don't want to remove the file, try removing its contents or most of itscontents that you don't need.

If your NPM registry requires authentication, try to rerun the npm logincommand.

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npm login

When you run the npm login command and enter your credentials, your .npmrcfile automatically gets updated.

# Remove your package-lock.json file and reinstall your dependencies

If the issue persists, remove your package-lock.json file and reinstall yourdependencies.

If you are on Windows, open your terminal in your project's directory (whereyour package.json file is) and run the following commands.

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# for Windowsrd /s /q "node_modules"del package-lock.jsondel -f yarn.locknpm cache clean --forcenpm install

If you are on macOS or Linux, open bash or zsh in your project's root directand run the following commands.

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# for macOS and Linuxrm -rf node_modulesrm -f package-lock.jsonrm -f yarn.locknpm cache clean --forcenpm install

Your old package-lock.json file might've had a resolved field that tries toaccess a private repository.

# Try to set your NPM registry correctly

If the issue persists, try to set your npm registry correctly.

Open your terminal and run the following commands.

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npm cache clean --forcenpm config set registry https://registry.npmjs.org

Check if the error is resolved after running the 2 commands.

You can also try to run the npm install command with the --registry option.

Use the following command.

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# ✅npm install --registry https://registry.npmjs.org

Instead of the following command.

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# ⛔️npm install

# Solving the error when using Azure

If you got the error when using Azure, try to:

1. Delete or temporarily rename your C:\Users\%username%\.npmrc file.
2. Open your terminal in the project's directory (where the local .npmrc islocated) and run the following command.

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npx vsts-npm-auth -config .npmrc

The syntax for the command is:

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npx vsts-npm-auth -config path-to-your\.npmrc

You can read more about the vsts-npm-auth package in thepackage's NPM page.

You can also try to run the npm logout command first.

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npm logout

Then run the vsts-npm-auth command.

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npx vsts-npm-auth -config .npmrc

If you use Azure, the issue also occurs if your personal access token expires.

You can renew your Personal access token in Azure DevOps > User Settings >Personal Access Tokens.

You can also try to log out and then log in.

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npm logoutnpm login

# Check if your package.json file contains a supported Node.js version

If the issue persists, check if your package.json file contains the Node.jsversion that you should be using when running npm install.

The supported Node.js versions are usually specified under the enginesproperty in package.json.

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"engines": { "npm": ">=8.0.0 <9.0.0", "node": ">=16.0.0 <17.0.0"}

If your package.json file contains a supported version range, make sure yourNode.js and NPM versions match.

You can get your Node.js and npm versions by issuing the following commands.

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node -vnpm -v

Usually, a safe bet is to install the LTS (long-term supported) Node.js version.

1. One way to download and install the LTS Node.js version is to use theofficial nodejs.org website.

2. Alternatively, you can use the nvm package to manage your Node.js version.

If you already have nvm installed, run the following 2 commands to install theLTS version and switch to it.

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nvm install --ltsnvm use --lts

If you don't have nvm installed, click on the link that relates to youroperating system:

• Install NVM on macOS and Linux
• Install NVM on Windows

After you install and switch to the LTS Node.js version, run the node -vcommand to verify.

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node -v

If you had to switch your Node.js version, you most likely will also have toreinstall your node modules.

If you are on Windows, open your terminal in your project's directory (whereyour package.json file is) and run the following commands.

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# for Windowsrd /s /q "node_modules"del package-lock.jsondel -f yarn.locknpm cache clean --forcenpm install

If you are on macOS or Linux, open bash or zsh in your project's root directand run the following commands.

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# for macOS and Linuxrm -rf node_modulesrm -f package-lock.jsonrm -f yarn.locknpm cache clean --forcenpm install

# Additional Resources

You can learn more about the related topics by checking out the followingtutorials:

• How to reset your NPM configuration to the default values
• The module was compiled against a different Node.js version using NODE_MODULE_VERSION
• Failed to load next.config.js Error: Not supported [Solved]
• gulp-sass 5 does not have a default Sass compiler [Solved]
• Error: getaddrinfo ENOTFOUND when making HTTP request [Fix]