If your material hold-down vacuum is missing the first troubleshooting step should be to establish if the Vacuum Pump is in fact running.
The easiest way to figure this out, is to go by the sound: at the table you will normally hear a hissing sound when the Vacuum Pump is running. If you don't hear this sound, then go the Vacuum Pump itself where you will easily notice if it is running or not: if it is silent, then it doesn't run.
Next steps in such a case is to check if the Vacuum control box needs to be Reset, or if there is a blown fuse:
Locate the Vacuum control box next to the vacuum pump (click to enlarge picture)
Press the Reset button on the Vacuum control box. (This resets the thermal cutout device inside the vacuum control box that may activate/trip if the vacuum pump is switched on and off often over a short period of time, for example when cutting small jobs). Note that the shape and color of your Vacuum control box may be different from the one shown on the picture
If the Vacuum Pump is stilll not starting, check and if required replace the fuse for the plug that supplies the single phase power to the vacuum control box - plug "6" on the picture below. The fuse size and -type depends on the local configuration
If required by local regulations, then have a qualified Electrical Engineer/Technician check the fuse!
Check that there is Three Phase supply to the vacuum pump. It could be that the supply is turned off or a fuse is blown. The Three Phase plug is marked as number "7" on the picture above. The fuse size and -type depends on the local configuration
If required by local regulations, then have a qualified Electrical Engineer/Technician to check the supply and fuses to the vacuum pump!