Error with AutomationTool when launching

Hi - I’m trying to deploy the basic HandheldAR template and run into the following issue (photo attached).

Specifically, the error is:

“Exception in thread “main” PKIX path building failed: unable to find valid certification path to requested target”

I’m working on macOS High Sierra and have Apple’s version of Java (Download Java for OS X 2017-001).
I’ve tried manually adding the certificate for the gradle distribution page, but that doesn’t seem to solve it.

Any ideas?