Is your nozzle too close to the bed?
If your nozzle is practically kissing the bed, then it would have no room for the melted filament to extrude. A too-close nozzle can cause your print to skip the first layers or even a blockage due to the backed up melted filament in the hot end.
You can configure either the height of the z-axis (easier) or print bed (harder). The latter is more difficult as you would have to level the bed and re-calibrate everything.