DAX Error: Unsupported Media Type

[nbufff]

Hi all, I'm trying to execute the query by using the REST API. It showed the error that Unsupported Media Type when I run below code. Is there any correction should be? Thanks for help!

let
body=" { 'queries': [ { 'query': 'EVALUATE SELECTCOLUMNS ('1#+SM+Missing+Region', '1#+SM+Missing+Region'[SKU]) } ], 'serializerSettings': { 'includeNulls': true } }",
Source = Json.Document(
Web.Contents(
"https://api.powerbi.com/v1.0/myorg/datasets/4cd14ac0-b612-48aa-980d-136d46a3e15c/executeQueries",
[
Headers=[Authorization="Bearer "&Token()],
Content=Text.ToBinary(body)
]
)
)
in
Source

[nbufff]

@lbendlin thanks for advise. Not sure how SAAS could get data from dataset since the data I need all from PBI dataset, could you pls help on it? Thanks.

[lbendlin]

I added the sample code.  Please try it out.

[lbendlin · Accepted solution]

You know you can do the same much simpler via the SSAS connector, right?

let
 Source=AnalysisServices.Database("powerbi://api.powerbi.com/v1.0/myorg/<workspace name", "<dataset name>", [Query="EVALUATE ...", Implementation="2.0"])
in
   Source

[nbufff]

YES. It works perfectly. Greatly Appreciate Your help!