[ovirt-users] User cannot create VMs having sufficient permissions to do so

Hi, We're running ovirt-4.1.6.2-1. We have a user that logs into the user portal and tries to create a VM, but a message claiming that "There is no Cluster on which you can create a VM. Please check Data Center status and Cluster permissions." shows up. However, this user has permissions on the cluster (both VmCreator and DiskProfileUser, and also has a Quota created on the Cluster which allows him to create VMs). When clicking on the 'New VM' button, all we see in the engine.log is: 2017-10-18 10:59:31,825+01 ERROR [org.ovirt.engine.core.bll.GetAllLabelsQuery] (default task-103) [c23549c6-37a4-48d7-923d-6618e027cdca] Query execution failed due to insufficient permissions. This user has pretty much the same permissions as thousands of users who can create VMs, but this one can't. How can we debug what's happening and how to solve it? Thanks.