OK, please try this when you get back home:
You will have to unplug the appliance and take a dry cloth, wipe inside the door, and clean the door seal.
After the cleaning is done, reconnect everything and plug it back.
Then use 2 cups of vinegar (1 in drawer and 1 in drum) or washing machine descaler and select an empty wash cycle on its hottest setting.
Please let it complete and then wait for around 1 hour before opening the door.
Now, after one hour unplug it again and then clean the drain pump filter located at the bottom front of appliance and clean the drum and door seal.
If you have ground coffee (you may pour it in a bowl/cup) and leave it for one day inside the drum.
Then next day after all this is done select another empty wash cycle on its hottest setting with washing machine descaler or detergent.
Let this complete then, leave it unplugged few hours this time with door open.
The problem should be resolved now and then you should not get any oil spots.
Please let me know how it goes.