1. After each wash, be sure to check that no foreign objects or substances are left in the drum. Check for any sign of damage or foreign objects.
2. Your appliance has small drainage holes in the door seal. Pull back the seal to check, if the drainage holes are blocked, use something like a toothpick to unblock it.
3. Check the pump filter for blockages. It may be that loose items such as coins, hair grips or buttons from garments could have got stuck in the pump housing, preventing the pump from removing waste water.
For more information, see the Cleaning the pump filter topic.
4. Check for blockages in the drain hose and any connected waste-water pipework that may prevent waste water draining effectively.
5. Ensure that any blanking plug or removable end has been taken off the waste pipe spigot.