added support in dgss

Author: TacoTechSharma

articles/trusted-signing/faq.yml

@@ -151,6 +151,7 @@ sections:
           | No certificates were found that met all the given criteria.         |  Check the dlib path, dlib version, dlib name, filename, and SignTool version. This error indicates that SignTool is attempting to pull certificates from your local computer instead of using Trusted Signing certificates. |
           | Error: "SignerSign() failed." (-2147024846/0x80070032)           |  Ensure that you're using the latest version of SignTool. |
           | Error code (-2147024885/0x8007000b)            |  For MSIX signing, this error indicates that the publisher in the manifest file doesn't match the certificate subject. Check the publisher that's listed in the manifest file. |
+          | Error code (-2147467259/0x80004005)            |  If you use Service Principal + certificate based authentication, check your Environment Variables listed under the table for ["Service principal with certificate"](https://learn.microsoft.com/dotnet/api/azure.identity.environmentcredential?view=azure-dotnet).|
           | No error codes, SignTool silently fails          |  Ensure that the relevant .NET runtime version is installed. |
           | `Azure.Identity.CredentialUnavailableException`      |  You might see this error in [environments outside Azure](https://github.com/Azure/azure-sdk-for-net/issues/29471). If you are working outside of Azure, we recommend that you add "exclude ManagedIdentity" to your manifest file. |
           | 403          |  - Check your Trusted Signing role.  <br>  - Check the Trusted Signing account name and the Trusted Signing certificate profile name in your *metadata.json* file. <br> - Check the dlib and dlib path. <br>  - Install C++ Redistributables from https://docs.microsoft.com/en-us/cpp/windows/latest-supported-vc-redist?view=msvc-170. <br>  - Check your .NET version, dlib version, and Windows SDK version. <br>  - Check if the Trusted Signing role is assigned to the identity that's trying to sign the file. <br>  - Check if the corresponding identity validation has a status of **Completed**.<br>  - Verify whether you access the Trusted Signing endpoint from this virtual machine or computer. Try executing the action on a different virtual machine or computer. The error might indicate a network issue. <br> - For Private Trust scenarios 403: The user object ID that does the signing is different from the user object ID that calls  `Get-azCodeSigningRootCert`. The appropriate object ID must have the role Trusted Signing Certificate Profile Signer.|