If you're using a distribution that uses systemd, start by adding the user to the system with the appropriate user and group permissions. Stop the QIE service, then modify the QIE systemd unit file (/etc/systemd/system/qie.service) and add the below bolded lines to the [Service] section:
[Service]
Type=simple
User=qie
Group=qie
Note: Make sure the user has full rights to the qie install folder (by default, /java/qie) as it will need to read and write files in that folder.
Save the systemd unit file, then start the QIE service.