Rest API: Add datasource user throws DMTS_DatasourceAccessRightIsNotSupportedError

[eduardocorpus]

I am trying to add a Service Principal to a Gateway datasource through the rest api (AddDatasourceUserWithHttpMessagesAsync) but keep getting a BadRequest response including the following error: DMTS_DatasourceAccessRightIsNotSupportedError.

I am authenticating as gateway administrator user and my request looks like this

{
"datasourceAccessRight": "ReadOverrideEffectiveIdentity",
"identifier": "<IDENTIFIER>",
"principalType": "App"
}

There are other questions pretty similar to mine: one didn't get a reply back and the other one solved it doing the exact same request as me.

https://community.powerbi.com/t5/Developer/DMTS-DatasourceAccessRightIsNotSupportedError-when-trying...

https://community.powerbi.com/t5/Developer/Change-a-datasource-in-a-dataset-that-s-connected-through...

I am trying to achieve the exact same thing but it is not working out.

Does anybody know if there something missing? Thanks.

[lbendlin]

Does it work in the sandbox?

https://docs.microsoft.com/en-us/rest/api/power-bi/gateways/adddatasourceuser

[eduardocorpus]

No, it didn't work. I got the same error: DMTS_DatasourceAccessRightIsNotSupportedError.