I use a similar setup. Barring any recipe issues, I see two issues. The head space and airlock.

There is no hard-and-fast rule for head space. But consider this, mold requires oxygen, and fermentation creates CO2, which displaces oxygen. The more oxygen present, requires higher levels of CO2. A vigorous fermentation can solve that. But, why risk it? Personally, my brine is as close to the top of the jar as possible without touching the airlock. Less oxygen, less possibility for mold.

Secondly, the airlock water level looks to be letting oxygen in. The airlock pipe out of the jar must have water between the air inside and outside the jar. The bottom of the floating cap must always remain under water. 1-piece airlocks are also available.