What do I say about why I left my last job? - first time posting

They always ask why I left, and I freeze. There are 16 people counting on me, so I am trying to be careful. I also do not want to seem like a risk. Do they ask follow-ups?

Practise it out loud with a friend. Mine felt natural after the third try.

Say it plainly and move on to what you can do. Interviewers usually move on if you do.