Grant privilege on instance

0

Hello,

I am trying to call this API so i can grant "readonly" privilege to a group on a instance.
/api/data/v4.0/db/{dbid}/elements/{id}/admin/privileges

I have added App.Elements.Admin.All permission.

But i get error: Invoke REST Web service - Request Url: https://domain/api/data/v4.0/db/1/elements/2450/admin/privileges Response Code: BadRequest (400) Exceptions: Rest service call failed. Http code BadRequest (400). Inspect log to get more information.

Can someone help?

Thank you.