Azure Media Service -Create Live Event API

I can get a bearer token and run some API’s but I am interested in create a live event.
https://docs.microsoft.com/en-us/rest/api/media/liveevents/create. When I send this it gets an error.
“code”: “InvalidResource”,

    "message": "The resource definition is invalid.

My Azure environment is a US Government tenant. My request is as follows
Put https://management.usgovcloudapi.net/subscriptions/:subscriptionId/resourceGroups/:resourceGroupName/providers/Microsoft.Media/mediaservices/:accountName/liveEvents/:liveEventName?api-version=2018-07-01

Thank you

An Invalid Resource error means your request is not well formed. It looks like you need to fill in for your own parameters. “:subscriptionId” for example should be the subscription ID you created in your Azure environment. Every parameter starting with “:” should be updated with your environment’s values.