IT Error Decoder

How to Fix Authentication_MissingOrMalformed

Error message

Authentication_MissingOrMalformed: Access Token missing or malformed.

If you're seeing "Authentication_MissingOrMalformed", you're not alone. Here's what it means, why it happens, and the steps to resolve it.

What this error means

The Microsoft Graph request was sent without a valid bearer token, or the token has expired.

Why this happens

You called a Graph cmdlet or REST endpoint before connecting, the session token expired, or a script reused a stale token.

Step-by-step fix

  1. Reconnect to Microsoft Graph with the scopes you need.

    command
    Connect-MgGraph -Scopes 'User.Read.All'
  2. Confirm a context now exists.

    command
    Get-MgContext
  3. If you are calling Graph REST directly, request a new token rather than reusing a cached one.

Affected products

Microsoft Graph PowerShell

Still broken? Try these

  • Clear cached credentials with `Disconnect-MgGraph` then reconnect.
  • If using app-only auth, verify the client secret/certificate is still valid.
  • Check the system clock — large clock skew can invalidate tokens.

Related errors

Frequently asked questions

What does "Authentication_MissingOrMalformed" mean?

The Microsoft Graph request was sent without a valid bearer token, or the token has expired.

What causes "Authentication_MissingOrMalformed"?

You called a Graph cmdlet or REST endpoint before connecting, the session token expired, or a script reused a stale token.

How do I fix "Authentication_MissingOrMalformed"?

1. Reconnect to Microsoft Graph with the scopes you need. 2. Confirm a context now exists. 3. If you are calling Graph REST directly, request a new token rather than reusing a cached one. Always test changes in a non-production environment first.

Browse more errors in Microsoft Graph PowerShell: Fix Microsoft Graph PowerShell errors. Insufficient privileges, invalid object ID, missing cmdlets, token problems, and more. Or paste your own error into the error decoder tool to find a match. You can also go back to the homepage to browse common errors by topic.