CMG Setup —Blank Subscription ID after signing in

When creating a new Cloud Management Gateway (CMG) I came across a scenario where I was able to successfully authenticate to Azure however the Subscription ID list was blank, even though I definitely did have a valid subscription in that tenant:

The culprit for this one turned out to be very simple (and my own fault). The account I had used to sign in was an Azure Global Administrator, but it was not the Owner of any subscriptions. The Microsoft documentation lists this as a requirement.

To give Owner rights to an account for a subscription, open the Azure Portal. Navigate to Cost Management + Billing > select the subscription you want to give access to > Access control (IAM) on the left.

The Role assignments tab will show the currently configured permissions:

To grant permissions, select Add > Add Role Assignment

In the new blade that opens, set the Role to Owner and then search for the account/group/object that you want to give that access to. Select the item in the list of results and click Save.

Back in the MECM Console, sign in to the account again and the Subscription ID list will now automatically fill with the subscription you just modified the permissions on: