Creating my first Elastic Database Job on Azure
The error on the portal is not clear, but you should be able to find details in deployment summary.

On portal go to your resource group and navigate to Deployment tab. There you can find history of the deployments with details about progress and errors.

The problem with Powershell looks like you don't set subscription context.

You should set the context to subscription which contains Reasource Group to which you want to deploy content.

To make this work use this example:
Example 1: Set the current subscription

After apply current subscription you should be able to see what is the real error during deployment.