> ## Documentation Index
> Fetch the complete documentation index at: https://docs.ntop.com/llms.txt
> Use this file to discover all available pages before exploring further.

# List Item Error

## Invalid list item at index

### About the error

**Issue:**
Your list has an error at the index indicated. Using a list as an input into another Block can lead to errors if the values used in the list are incorrect.

**Applies to:**

* Any block that can accept a list type as input.
  * Common examples include:
    * Using an invalid item in an Implicit Body List, then using it as a Body input for a Mesh from Implicit Body. This results in errors when using the Mesh from Implicit Body as an input into other Blocks.

**Cause:**

* The values used in a list item are incorrect, causing a block to fail when it builds.
* Using a list as an input into another Block can lead to errors if the values used in the list are incorrect.

**Solution:**

* In the error message, note the index number of the list item causing the error. Use the index to identify the list item causing the error. All nTop lists begin at index 0. Please use the Error Documentation pages to troubleshoot.

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