Some of this you've already done but it's well worth checking it again.
First, check the drain hose where it connects to the house drains.
If it's onto a connection, take the hose off and check both the hose and connection for a blockage.
If ok, put a dish in front of the screw cap.
Slacken it a little to drain the water out.
Tighten it to stop the water when you need to empty the dish.
Once you empty the water out, fully unscrew the cap and pull it out.
Clean out the debris in there.
Look in and you'll see the pump impellor.
Ensure this can turn, turn it with a screwdriver.
There should be resistance and it then "pings" round.
Take the laundry out.
With the filter out, select a spin or drain only programme.
Look in and see if the impellor is spinning.
If it is, refit the cap.
Try the machine again.
Hope this helps
Let me know how it goes or if you need more help