Disk Export URL Error: AuthenticationFailed

Question

Disk Export URL Error: AuthenticationFailed

Burns 30

I am trying to download a VHD of a Virtual Machine that I migrated from a local Hyper-V host and when I access the generated SAS URL I get the following error:

<Error>
  <Code>AuthenticationFailed</Code>

  <Message>
Server failed to authenticate the request. Make sure the value of Authorization header is formed 	    correctly including the signature. RequestId:XXX Time:2023-06-20T19:08:47.5440703Z

  </Message>
  <AuthenticationErrorDetail>

  SAS identifier cannot be found for specified signed identifier

  </AuthenticationErrorDetail>
</Error>

My user has the Owner, Contributor, and Data Operator for Managed Disks roles assigned at the Subscription level (shown below), and I have enabled data access authentication mode via the documentation here: https://learn.microsoft.com/en-us/azure/virtual-machines/windows/download-vhd?tabs=azure-portal#enable-data-access-authentication-mode

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Sumarigo-MSFT 47,466 Reputation points Microsoft Employee Moderator

2023-06-21T11:54:06.52+00:00

@Burns Just checking in to see if the above answer helped. If this answers your query, do click "Accept the answer” for the same, which might be beneficial to other community members reading this thread. And, if you have any further query do let us know.

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Sumarigo-MSFT 47,466 Reputation points Microsoft Employee Moderator

2023-06-21T11:54:06.52+00:00

@Burns Just checking in to see if the above answer helped. If this answers your query, do click "Accept the answer” for the same, which might be beneficial to other community members reading this thread. And, if you have any further query do let us know.

Answer 1

Jackson Martins 10,606 MVP Volunteer Moderator

Hi @burns

Shared Access Signatures are time-limited. Once the end time has passed, the SAS URL will no longer work. Try to generate a new SAS URL and see if you can access the resource with that.

Try to check the firewall on Storage Account:

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If you enable the option "Enabled from selected virtual network and IP address" means the firewall is enabled:

Sem título

You also can create a custom role and give the necessary permission to download the vhd:

Go to Subscription -> IAM -> Add -> Add Custom role:

custom role

Select Microsoft.Compute/disks/Action:

custom role2

You can also remove the authentication mode by unchecking the option when creating the URL:

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Get in touch if you need more help with this issue.

--please don't forget to "[Accept the answer]" if the reply is helpful--

Jackson Martins 10,606 Reputation points MVP Volunteer Moderator

2023-06-20T21:35:43.7+00:00

Completing my previous answer, you can create a custom role, and give the necessary permission to download the vhd:

Go to Subscription -> IAM -> Add -> Add Custom role:

Select Microsoft.Compute/disks/Action:
Burns 30 Reputation points

2023-06-21T16:51:11.0433333+00:00

Thank you Jackson. I believe the issue was the networking and public access. It is working now.

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Disk Export URL Error: AuthenticationFailed

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