Unable to create vnet gateway, get error "could not find resource when attempting to deploy"

From @perthguppy via Twitter

"@AzureSupport Seem unable to create vNet Gateways on Az portal atm. Says could not find resource when attempt to deploy? Worked recently."

https://twitter.com/perthguppy/status/730611244231581697

Thanks,

@AzureSupport