I am trying to setup a Service Account for the credentials of a BigQuery data source in Data Studio (now looker studio). I have followed the instructions here.
Everything is set up but when i want to add the service account to the credentials of the data source i get the following error: This service account can't access the underlying data set.
I am using a custom query which only access one data set as data source.
I made sure that the service account has Big Query Data Viewer access to he data set accessed in the query and to go even further i gave it access Big Query Data Viewer at the project level. I have also waited over 30 minutes but the problem is still there.
It turned out i had everything set up as explained in the documentation.
The problem was that within my Data Set one of the tables i was accessing in the query was an external table stored in a bucket in Google Cloud Storage. The service account did not have read permission on that bucket.
I grant it read permissions to the Storage Bucket and it finally worked.