in aspnet/Microsoft.Samples.XMLA.HTTP/Tester/Program.cs [274:293]
static async Task<string> GetBearerTokenAsync(string clientId, string clientSecret, string tenantId)
{
var redirectUri = new Uri("urn:ietf:wg:oauth:2.0:oob");
//use this resourceId for Power BI Premium
var resourceId = "https://analysis.windows.net/powerbi/api";
//use this resourceId for Azure Analysis Services
//var resourceId = "https://*.asazure.windows.net";
var authority = $"https://login.microsoftonline.com/{tenantId}";
// var clientId = "cf710c6e-dfcc-4fa8-a093-d47294e44c66";
var ctx = new AuthenticationContext(authority);
var token = await ctx.AcquireTokenAsync(resourceId, new ClientCredential(clientId,clientSecret));
return token.AccessToken;
}