at a loss

They said that they believed the consultants had a "personal grudge" against Letby, which they were "at a loss" to understand.

Crystal is happy to be alive but at a loss over what to do next.

They’re both at a loss as to how to make things right in their lives, and in a world increasingly barren of understanding and farther from whatever name one has for divine goodness.

In SBS cases, he said, many of the defendants find themselves at a loss as to how to argue their innocence when their conviction was based on medical experts.

I was gracious in accepting but was kind of at a loss in terms of begrudgingly having to carry around a lone flower all night.