InvalidTemplateDeployment. See Inner Errors for Details while testing deployment of an ARM Template

While testing the deployment of an ARM template I received the following error message.

If you said to yourself “That’s great, however, how do I find the inner errors for details?” You’re in luck, because I am going to tell you!

First, save the deployment test to a variable like the following.

If we look at the $test variable itself, we can see a details section at the bottom.

What happens if we look at $test.details? More details that aren’t particularly helpful!

Alright. So what happens if we look at the details of the details? We run out of details about details, but we do get the information we were looking for to start with.