Automated Power Down Of Windows Virtual Machine Fails with Authorisation Issue

Question

Automated Power Down Of Windows Virtual Machine Fails with Authorisation Issue

Cossy Cosmas 25

I have created an automated task in Azure to power down a Windows 2019 Datacenter edition o/s server but it failed with the following error message:

{ "error": { "code": "AuthenticationFailed", "message": "Authentication failed. The 'Authorization' header is missing." }}

Does anyone know what might be causing the issue?

The automated tasks were created using a colleagues user account but that account should have sufficient privileges on all of the resources in the subscription.

Any advice appreciated!

Cossy

anashetty 3,060 Reputation points Microsoft External Staff

2025-04-14T15:37:05.6133333+00:00

Hello Cossy Cosmas,If your automation script doesn't include a valid access token in the Authorization header, Azure will reject the request. Check whether authentication token is valid and has not expired.

Document: No authentication provided

You need to pass the auth header in the request. The article below calls out options (using Postman) to authenticate to Azure Resource Manager Authenticate Postman against Azure Service
For your reference: The Authorization header is missing

If you have any further queries, let me know. If the information is helpful, please click on Upvote.
Cossy Cosmas 25 Reputation points

2025-04-15T08:00:21.0133333+00:00

Hi Anashetty.

I am not using a script, I am using the standard 'Automated Tasks' feature available with each and every virtual machine.

Does a script still apply in this context?

Regards,

Cossy
Cossy Cosmas 25 Reputation points

2025-04-16T14:50:49.6933333+00:00

That's great, thanks for your advice! :)
anashetty 3,060 Reputation points Microsoft External Staff

2025-04-17T10:52:53.62+00:00

Hi Cossy Cosmas,

As the information has been helpful to you, could you please Accept Answer, as it can be helpful to others in the community.

Accepted answer

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anashetty 3,060 Reputation points Microsoft External Staff

2025-04-14T15:37:05.6133333+00:00

Hello Cossy Cosmas,If your automation script doesn't include a valid access token in the Authorization header, Azure will reject the request. Check whether authentication token is valid and has not expired.

Document: No authentication provided

You need to pass the auth header in the request. The article below calls out options (using Postman) to authenticate to Azure Resource Manager Authenticate Postman against Azure Service
For your reference: The Authorization header is missing

If you have any further queries, let me know. If the information is helpful, please click on Upvote.
Cossy Cosmas 25 Reputation points

2025-04-15T08:00:21.0133333+00:00

Hi Anashetty.

I am not using a script, I am using the standard 'Automated Tasks' feature available with each and every virtual machine.

Does a script still apply in this context?

Regards,

Cossy
Cossy Cosmas 25 Reputation points

2025-04-16T14:50:49.6933333+00:00

That's great, thanks for your advice! :)
anashetty 3,060 Reputation points Microsoft External Staff

2025-04-17T10:52:53.62+00:00

Hi Cossy Cosmas,

As the information has been helpful to you, could you please Accept Answer, as it can be helpful to others in the community.

Answer 1

Hi Cossy Cosmas,

Thank you for confirming. You don't require a script, these scheduled tasks utilize Azure Logic Apps or Azure Automation to execute the action. This means that authentication is still necessary, likely occurring through your Azure account credentials or a service principal established during the task setup.

Check the role assignments in Azure portal: VM > Access control (IAM) > Role assignments
See that you have Contributor role or Virtual Machine Contributor role.

Recreate the Task with Proper Permissions: Delete the existing task from the VM > Automation > Tasks blade.
Recreate the task using your own account, which is the recommended way, or A service account with Owner or Contributor rights. Ensure the identity creating the task has at least the Virtual Machine Contributor role.

Check Microsoft.Compute Resource provider: Go to Subscriptions → Your subscription → Resource providers. Ensure Microsoft.Compute is registered. If not, click "Register"

If you have any further queries, let me know. If the information is helpful, please click on Upvote.

anashetty 3,060 Reputation points Microsoft External Staff

2025-04-16T15:44:50.08+00:00

Hi Cossy Cosmas,

As the information has been helpful to you, could you please Accept Answer, as it can be helpful to others in the community.

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Automated Power Down Of Windows Virtual Machine Fails with Authorisation Issue

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