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

# upstream_unavailable

> Upstream unavailable (HTTP 503)

| | |
| - | - |
| HTTP status | `503` |
| OpenAI `type` | `server_error` |
| Anthropic `type` | `overloaded_error` |
| Retry | Yes. Error responses carry `x-should-retry: true`. |

## What it means

The model runtime is unavailable or overloaded, even after Antara's retries.

## What to do

Retry after `Retry-After`.


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