Translation of "못해서" in English

필요한 기술을 배우지 못해서 걱정이라고요.

that they're worried that they're not getting the skills that they need.

확신하지 못해서 중립성향을 띄는 것이 아니라

They're gray not because they're unsure,

제가 문화를 잘 이해하지 못해서 무서웠던 겁니다.

was only scary because I didn't fully understand the culture.