Hi Alvin IT,
I'm not an admin here but I would try to help you )))) so, from the first point of view the error message you're encountering indicates that the deployment of your Azure Virtual Desktop (AVD) host pool failed due to an issue with the template deployment. First of all, I would like to give you a links whiches would help you to fix that issue.
Azure Virtual Desktop Documentation
https://learn.microsoft.com/en-us/azure/virtual-desktop/
Troubleshooting ARM Deployment Issues
Validating ARM Templates
InvalidTemplateDeployment Error
Logs and Monitoring
So, now anout my thinks what to do next... the error message suggests looking at the inner errors for more details. You can find these details by navigating to the deployment operations in the Azure portal. Go to the Azure portal -> Resource Groups -> Your Resource Group -> Deployments. Find the failed deployment and click on it to see the detailed error messages.
Ensure that the ARM (Azure Resource Manager) template you are using is valid. You can use the Azure Resource Manager Tools extension in Visual Studio Code to validate the template or you can use the Azure CLI to validate the template
az deployment group validate --resource-group <YourResourceGroup> --template-file <YourTemplateFile.json> --parameters <YourParametersFile.json> (if I'm correct:)
Ensure that your Azure subscription has sufficient quotas for the resources you are trying to deploy (e.g., vCPUs, memory, etc.).
Pls check your quotas in the Azure portal by navigating to Subscriptions -> Your Subscription -> Usage + quotas.
Ensure that the network configuration like virtual network, subnet, NSGs is correctly set up and does not have any conflicts. Verify that the subnet you are using for the host pool has enough available IP addresses. Ensure that the account you are using to deploy the host pool has the necessary permissions to create resources in the specified resource group and subscription. The account should have at least the Contributor role assigned. As well check the activity log and metrics for any additional insights into what might have caused the failure.
Navigate to the Azure portal -> Resource Groups -> Your Resource Group -> Activity log.
If you identified any issues with the template or parameters, correct them and try to re-deploy the host pool.
I hope that would help you.
rgds,
Alex