The skirt looks ok, which tends to rule out the most extreme flow or blockage issues. However, skirt/bottom layer can be over-squashed so not ideal for calibration.
I assume this is intended to be a 100% layer rather than infill. It looks maybelike you're achieving about 50% infill, which is a good clue.
I guessed (and confirmed in comments) that you are set for 3mm filament, but using 1.75? (I had cura default to this on me not long ago, despite printing perfectly before, and no intentional changes). One easy check would have been to try one of the provided pre-sliced models that came with the printer.
The effect of configuring for 3mm filament is to reduce flow by a factor of 3 (diameter squared), so even a 50% over extrusion still leaves you with less than half the plastic volume required.
After fixing this, you will need to raise the Z-home position slightly to enable the first layer to extrude properly.