If you notice any signs of "mold" or fungus on the soil, it's a sign that the soil is staying wet for too long or that the plant isn't getting enough light. It's important to only fill the water reservoir of your easyplant once the soil is dry.
Note, in most cases this isn't a true mold and is actually a type of fungus, similar to most mushrooms. It is not dangerous to your plant or your health, and is mainly a cosmetic issue.
How do I fix it?
If the fungus is just on the surface, scoop out the affected soil; there shouldn't be a need to replace any of the soil, but if some of the soil does need to be replaced, coco-coir can be used.
Once the fungus has been removed or if the mold is throughout the soil, place the plant in a more brightly lit spot with good air flow to let the soil dry out.
Adding a sprinkle of cinnamon to the top of the soil will help prevent mold from coming back, since it's a natural antifungal.
If the fungus is persistent, poking a few holes in the top of the soil will also help more airflow get down into the soil.