Error: 401 Unauthorized: [no body]

I follow this document create java embed powerbi

https://learn.microsoft.com/en-us/power-bi/developer/embedded/embed-sample-for-customers?tabs=java#power-bi-username-and-password 

But Authorization was not successful

request message:

Error Details:

Error: 401 Unauthorized: [no body]

error line is the following code in com.embedsample.appownsdata.services.PowerBIService.java

ResponseEntity<String> response = getReportRestTemplate.exchange(endPointUrl, HttpMethod.GET, reqEntity, String.class);

I only filled in the parameter values in Config.java

Thanks for your help !