I have completed this piece however when running the code my default browser launches but does not load the intranet page. Instead, it sits open and then a second browser launches, not my default, and it successfully logs in as expected. Not sure why both browsers are launching and why the instructions only execute in second browser.
You should see from logs what happened. If your default id Chrome, you can check if it has update pending. Open Available Browser has order how it tries to open browsers.