How to find leak in washing machine?
There is some water leak inside your appliance.

You can diagnose it carefully. First statically, then you can try to observe the problem when the appliance is running.


Ensure being safe - check your loose clothes, long hair, gloves or jewellery, the following operation is at your own risk.
Remove the covers of the washing machine, so you can see inside, but keep everything plugged in.


rear cover
top cover (optional)
 
This is only for observation. Do not touch anything inside.  

Pour some water into open door, then inspect the bottom of the appliance case for accumulating water (use torch to see better). If the water starts appearing, skip to the last step below.
Start the washing cycle (can be without load, without detergent).
Using bright torch, inspect the bottom of the appliance case for accumulating water and try to identify location where the water comes in. (Do not get close, do not touch, stay in safe distance, just observe.)
If you got an idea, end the cycle, drain the water, unplug the machine completely and continue with regular repair/replacement of the defective part. If you did not get an idea, then this is probably beyond your DIY capabilities and call repair service.