Looker Studio Service Account Credentials

[ScottHall]

Hi there,

I am trying to use a Google service account to authenticate and authorise access to data as defined in this documentation: https://support.google.com/looker-studio/answer/6371135#zippy=%2Cin-this-article%2Cservice-account-c...
I have made sure that all the access is configured correctly and looked at all the help in this article: https://support.google.com/looker-studio/answer/10835295#errors&zippy=%2Cin-this-article

But I still get the following error when assigning the service account as the data credentials: 
Can anyone help?