1st 2 lights flashing is fault F03 meaning The drain pump has been energised for 4 minutes, but the pressure switch has not reset to the empty position.
The drain pump is fed from the wash pump; therefore an open circuit wash pump could stop the drain pump from working.
A jammed drain pump or blockage in the outlet hose or plumbing.
A blocked pressure chamber or pressure switch air tube.
A faulty pressure switch.
Check wiring to pump and module connections.
If all the above are OK, replace the module.

Make sure the water is on and the waste pipe is not blocked.
The filters within the d/w need to be carefully removed, cleaned and replaced. Make sure they are firmly located.
The pump underneath can be blocked.
Switch off electricity (I didn't...got a serious shock!). A big towel down to absorb water.
Tip d/w onto its back. Remove six screws in base plate. disconnet wiring plug from the float switch (attached to the base plate) noting the way it fixes.
Small white pump to right heading back. Remove single screw and twist body.
Disconnect from wiring plus (again noting which way it fits).
Using a star pattern driver remove three screws arounf the middle of the pump. Separate the two halves.
Clean thoroughly but carefully taking care not to get water into the electrical parts.
Reassemble everything and put the d/w upright.
Test

Sounds like you have a leak in the base, tip the unit over on the side to see if water pours out if so you need to check what base item is leaking.