ERROR CODES / ENGLISH
Relay 504 Gateway Timeout: long requests time out
How a 504 differs from a 502, why long answers trigger it, and what to change on the client and on the relay side.
Reviewed 2026-11-13 · ERROR CODES / 504 · Chinese detail: 完整中文页
What it means
A 504 means the gateway waited for the upstream until it timed out. Long answers are the most likely to trigger it.
504 Gateway TimeoutA 502 means the gateway could not reach a working upstream at all; a 504 means it reached the upstream but did not receive a response in time. Both errors come from the site's gateway, not from your client.
Common causes
| Share | Cause |
|---|---|
| 55% | The site's upstream timeout is set too short |
| 25% | The upstream responds slowly |
| 20% | The request itself is too long |
How to confirm
Send a short request first. If short requests succeed and long ones fail, the timeout setting is the likely cause. If every request returns 504, the upstream is down. If switching sites fixes it, the original site's configuration is at fault.
Fix
On your side:
- Shorten the single request (split it into segments).
- Turn off streaming, or switch to non-streaming.
- Switch site.
On the service side:
- The site needs to raise its read timeout.
If it still fails
| Symptom | Responsible party |
|---|---|
| Short requests work | Timeout setting |
| All requests return 504 | Upstream down |
| Switching site fixes it | Site configuration |
For long-form generation, prefer sites with generous timeout settings. A 504 tells you the gateway gave up, not that the model produced a bad answer.
General guidance, not a statement about any specific provider. For measured data, see the relay directory and method.