Creating resource group fails with "does not have authorization"

I've been stepping through MS Azure training docs for quite a while now. I find that the exercises consistently work. However, today I was going through "Run Docker containers with Azure Container Instances Exercise - Run Azure Container Instances", and I'm getting a consistent error.

The first step, where I have to run this:

az group create --name learn-deploy-aci-rg --location eastus

Consistently fails with:

The client 'live.com#xxxxxx@gmail.com' with object id'xxxxxxx' does not have authorization toperform action'Microsoft.Resources/subscriptions/resourcegroups/write' over scope'/subscriptions/xxxxxxxx/resourcegroups/learn-deploy-aci-rg'or the scope is invalid. If access was recently granted, pleaserefresh your credentials.

I tried logging out of the training account and logging back in, but I get the same result when I attempt this again.