This kind of problem sometimes occurs when syncing a full node. If you ever see that both Bitcoin Knots or Bitcoin Core sometimes suddenly crash or close on their own, especially during syncing. If you want to find out exactly where the problem is, you need to look at the logs. Sometimes this happens because of problems with the logs. Usually, there are logs like this:
Since Knots is built on Core, it also keeps logs in the same place. By opening that file, you will understand at which stage it crashed or closed. And you can find the solution to the problem from there.