The API returns an error

The API service may fail at processing the request, for their own reasons.

For instance, DeepSeek might return error "Unsuccessful request: POST https://api.deepseek.com/chat/completions resulted in a 200 OK response'".

Claude may return the error "Server error: POST https://api.anthropic.com/v1/messages resulted in a 529 response:\n{\"type\":\"error\",\"error\":{\"type\":\"overloaded_error\",\"message\":\"Overloaded\"}}"

Whenever any of these happens, you can then trigger the translation again (eg: via the Bulk Actions), until it works.