Why does my starter keep growing mold?

Hi everyone! So I'm new to sourdough and I'm trying to get my first start up and running but I've had two failures before I can even make any bread.

I started my first starter a few weeks ago and did what I was instructed to do (1/2 cup flour, 1/4 cup water mixed in a jar, lid on but not tightened so it can breathe, discard half and feed it another 1/2 cup flour and 1/4 cup water every 24 hours)

The first time it started out well and looked like it was growing within a few days, but then it started to smell bad and a few days later there was fuzzy black mold growing on the sides of the jar above the starter.

I researched why that might happen and was told that it might be in too humid a spot, and that the cleanliness might not have been enough.

So I started a second starter, now storing it in a cool dark cabinet and washing my hands/all utensils when I feed to starter. I was scraping the sides as well because I was told that helps. I even switched it out to a new jar every few days so it would stay clean. This one lasted longer (a week or so) and again looked like it was becoming active because it was growing and had bubbles in it. But I just checked last night and AGAIN it is growing that same black fuzzy mold on the sides.

What am I doing wrong? Is there an essential step in missing?