Samsung 5e Error - No debris in filter?

Hi,

I have a Samsung washing machine (WF-B1456GW) and I'm getting the 5e error code. I have drained the machine and cleared the filter.

The first time I cleared it there was some items in the filter but I keep getting the code and there is now nothing in the filter.

I have taken the pump out and disconnected all the hoses and checked for any blockage, apart from a small amount of limescale there wasn't any blockage.

The impeller seems to spin freely when removed from the pump but is restriced when reconnected to the
pump which I presume is normal?

When I put the pump back together it worked fine for the next run, I ran a drain cycle and it worked and then ran a full cycle and it worked with no problems.

The second run I got the 5e error code again. Any ideas would be gratefully received.

Cheers