Gateway info from Power BI API in PowerShell

Hi,

So Ive got all manner of data out of the Power BI REST API using PowerShell, using both a Native & Web app.

Im trying to hit this API and getting a 401 across the board though I got it working a few weeks back strangely...

https://api.powerbi.com/v1.0/myorg/gateways

The user is an admin on all of my data Gateways & the apps have all the perms in Power BI.

Is there a template example someone could provide, where this just works or any ideas? Its obviously auth but I dont see what Id need to alter (or even how I got some of it working a few weeks back).

Here's the script Im using...

https://github.com/cporteou/Powershell_PowerBI/blob/master/PowerBI_API_Gateway.ps1

Thanks