It not about GloriaFood integration. It uses MessageServer for recording tickets to SambaPOS. But it’s a WindowsService. Because of this it cant print usb printers. Please use network printers for this.
To clarify, you CAN print to USB printers, but SambaPOS Messaging Service needs to be set to run as a user with Administrator rights on the system. By default it is installed to run as LocalSystem which does not give access to USB devices. I believe this is actually mentioned somewhere on tutorials but may not be reflected on the actual instructions on the KB.
Unless you specifically did what I showed above already, it will have been installed as LocalSystem, which is not Administrator and does not have access to USB devices.
I have set up many before, i came across this very issue a few years back and resolved with this, and been fine since.