PowerBI REST API to get dataset id does not work, keep getting forbidden error

I've been trying to use the PowerBI REST API Get datsets: https://docs.microsoft.com/en-us/rest/api/power-bi/datasets/getdatasets, but when I run the GET request, I keep getting Forbidden.  But I've checked according to here (https://docs.microsoft.com/en-us/power-bi/developer/register-app) that all my permissions have been set for reading and writing.

Why is this the case?  Also, can you get the dataset id directly from the Push URL of a Power BI streaming dataset?

Thanks.