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

# Trace errors documentation

This page contains the documentation for the trace errors.\
There are 2 types of trace errors:

* 400 errors : client error : the request is invalid.
* 500 errors : engine error : an unexpected error occurred.

## Classified errors

### 001

This error is returned when creating a link and the data has exceeded the maximum size (5MB).

### 006

This error is returned when the user is not authorized to perform the action.
The action is not in the list of the next actions available from the group selected.

### 016

This error is returned when the `workflowId` does not exist, or automation is not allowed on this target workflow.

### 033

Error occured during the creation of a [scheduler](/configuration/action/effects#external-functions) : the input might be invalid.
For example: the cron expression or timestamp is invalid, or the scheduler already exists.

## Non classified error

### 000

An error occurred while creating a link, that has not been classified in another error, but is not an engine error (probably wrong input)

### EXEC-JS

This error is returned when the execution of the action failed.
This is occuring when the action's [effects](/configuration/action/effects) (backend business logic) fails.
This could be because :

* of a throw occurring in the effects.
* of an [external function](/configuration/action/effects#external-functions) failing.
* of a Javascript error inside the effects.

### DSL-ERROR

An error caused by a Throw Statement, when a throw occurred in the effects.

### ERR-500

An unexpected system error occurred that could not be classified into a specific error category. This typically indicates an internal server issue or an unhandled exception.

When it occurs:

* Unhandled exceptions in the system
* Database connection failures
* Unexpected errors that don't match any specific error patterns
* System-level failures that require investigation

Resolution: Contact support if the issue persists.