PipelineJob using a dedicated service account

[mans123]

When I submit my pipelinejob (submit)

job = PipelineJob(...)
job.submit(
    service_account='<PII removed by staff>'
)

I get the following error message:

grpc_message:"You do not have permission to act as service_account: <PII removed by staff>. (or it may not exist)."

I am the owner of the project and when I go through the console to create a pipeline job, there is no issue in specifying another service account to run as. It all works if I remove the service_account parameter, so the default account is used. Any idea what the issue can be?

Thanks!