> ## Documentation index
> Fetch the complete documentation index at: https://dify-docs.docs7.io/llms.txt
> Ask it with GET https://dify-docs.docs7.io/ask?q=<keywords or question>. Short keywords rank best.
> Use these to discover all available pages before exploring further.

# Error Types

Each node type throws specific error classes that help you understand what went wrong and how to fix it.

## Node-specific errors

<Tabs>
<Tab title="Code" icon="code">

`CodeNodeError`
<Info>Your Python or JavaScript code threw an exception during execution</Info>

<Frame>
  ![Code Error](https://assets-docs.dify.ai/2024/12/c86b11af7f92368180ea1bac38d77083.png)
</Frame>

`OutputValidationError`
<Info>The data type your code returned doesn't match the output variable type you configured</Info>

`DepthLimitError`
<Info>Your code created nested data structures deeper than 5 levels</Info>

`CodeExecutionError`
<Info>The sandbox service couldn't execute your code - usually means the service is down</Info>

<Frame>
  ![CodeExecutionError](https://assets-docs.dify.ai/2024/12/ab8cae01a590b037017dfe9ea4dbbb8b.png)
</Frame>

</Tab>
<Tab title="LLM" icon="brain">

`VariableNotFoundError`
<Info>Your prompt template references a variable that doesn't exist in the workflow context</Info>

<Frame>
  ![VariableNotFoundError](https://assets-docs.dify.ai/2024/12/f20c5fbde345144de6183374ab277662.png)
</Frame>

`InvalidContextStructureError`
<Info>You passed an array or object to the context field, which only accepts strings</Info>

`NoPromptFoundError`
<Info>The prompt field is completely empty</Info>

`ModelNotExistError`
<Info>No model is selected in the LLM node configuration</Info>

`LLMModeRequiredError`
<Info>The selected model doesn't have valid API credentials configured</Info>

`InvalidVariableTypeError`
<Info>Your prompt template isn't valid Jinja2 syntax or plain text format</Info>

<Frame>
  ![InvalidVariableTypeError](https://assets-docs.dify.ai/2024/12/9882f7a5ee544508ba11b51fb469a911.png)
</Frame>

</Tab>
<Tab title="HTTP Request" icon="globe">

`AuthorizationConfigError`
<Info>Missing or invalid authentication configuration for the API endpoint</Info>

`InvalidHttpMethodError`
<Info>HTTP method must be GET, HEAD, POST, PUT, PATCH, or DELETE</Info>

`ResponseSizeError`
<Info>API response exceeded the 10MB size limit</Info>

`FileFetchError`
<Info>Couldn't retrieve a file variable referenced in the request</Info>

`InvalidURLError`
<Info>The URL format is malformed or unreachable</Info>

</Tab>
<Tab title="Tool" icon="wrench">

`ToolParameterError`
<Info>Parameters passed to the tool don't match its expected schema</Info>

`ToolFileError`
<Info>The tool couldn't access required files</Info>

`ToolInvokeError`
<Info>The external tool API returned an error during execution</Info>

<p align="center">

<Frame>
  ![](https://assets-docs.dify.ai/2024/12/84af0831b7cb23e64159dfbba80e9b28.jpg)
</Frame>

</p>

`ToolProviderNotFoundError`
<Info>The tool provider isn't installed or configured properly</Info>

</Tab>
</Tabs>

## System-level errors

`InvokeConnectionError`
<Info>Network connection failed to the external service</Info>

`InvokeServerUnavailableError` 
<Info>External service returned a 503 status or is temporarily down</Info>

`InvokeRateLimitError`
<Info>You've hit rate limits on the API or model provider</Info>

`QuotaExceededError`
<Info>Your usage quota has been exceeded for this service</Info>