Hi @ReshmiKaruturi ,
we would need to see the data going into the tool, and the configuration to determine the error.
M.
Here's a quick intro video on how to use the tool:
https://www.youtube.com/watch?v=D2KCts5jhRo
Please share an example dataset or at least a snapshot of your workflow/Nearest Neighbor Tool config so we can help diagnose the issue.