> ## Documentation Index
> Fetch the complete documentation index at: https://docs.nx1cloud.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Errors

> NexusOne API error responses and request size limits for handling failures and constraints.

While interacting with the NexusOne API, you might encounter several HTTP error responses
and request size limits.

## HTTP error responses

You should find the following HTTP error responses when interacting with NexusOne via the API:

* **400 - Bad request**: The request syntax is invalid. This might be an invalid query parameter, an invalid file ID format,
  or not providing a local file or source URL when uploading a file.
* **401 - Unauthorized**: The request uses an invalid generated OAuth 2.0 access token or API key.
* **403 - Forbidden**: Your generated OAuth 2.0 access token or API key doesn't have enough permission to access the resource.
* **404 - Not found**: The requested resource doesn't exist. This might be a data quality rule or table.
* **500 - Internal server error**: An unexpected error has occurred within NexusOne's server.

## Request size limits

To optimize performance, there are a few request size limits set:

* **Files**: When uploading a local file or a file from a source URL.
  * **Limit**: 5 GB
  * **Endpoints**:
    * [Upload File URL](/api-reference/endpoints/files/upload-file-url)
    * [Upload File](/api-reference/endpoints/files/upload-file)

* **Ask**: Context window when asking the system to generate a SQL query.
  * **Limit**: Varies based on the AI model used by the client.
  * **Endpoints**:
    * [Asks a question about a data domain](/api-reference/endpoints/queries-formerly-cards/ask-a-question-about-a-data-domain)
    * [Ask eng](/api-reference/endpoints/data-engineering/ask-eng)
    * [Suggest](/api-reference/endpoints/data-quality/suggest)