LG WASHER drain hose will only work now if directed to floor drain

I have done everything suggested after I got an OE error message on my LG washer. Strange thing is that when the drain hose fell to the floor, after I took it out of the inlet in the laundry tub whilst machine on, water starting flowing out at a steady rate. I played around with the direction of the hose but as end of the hose went higher then 40cm from the floor water would stop pumping through. I turned off the power at the wall and put the washing machine on a tub cycle.

I have been able to wash with no errors happening if I direct drain hose to drainage hole in Laundry floor. Not ideal to leave it like this as the washing machine needs to be placed in middle of laundry room.

1. I opened up drain filter - nice and clean
2. Checked pump impeller whilst drain filter taken out. Moved freely. I also chose a spin cycle and I can see impeller spinning beautifully.
3. I Blew air into hose. I could feel air coming out other end near filter. I also ran water down the hose. Flowed out with no problem the other end.

What to do now? Has the pump lost pressure and that is why it cannot work with hose directed upwards towards laundry tub (90cm above the floor)? I can hear motor working and see impeller working.