Received an interesting issue today from a customer running their maintenance workflow.
They had no issues with running their maintenance workflow when using their personal administration accounts but ran into the following errors in the utility logs when using a service account in the login object.
20160924/120115.262 - U0032203 Logon with user 'CUSTUSER/%'.
20160924/120115.278 - U0032206 Logon with user 'CUSTUSER/%' was not successful. Access denied.
The solution here was to create a dummy job using the login of the user that the job was using (the service account), then copied this to 0 and everywhere else and our Maintenance job worked properly.
We've also seen this error resolved in the past when there is a user object for that user in each client the utilities touch, including client 0.