What it means
With a 408 the slow party is the client, not the server: the request didn't arrive in full within the allowed time. It often happens on slow or unstable connections, large uploads, or when the browser opens a connection but never uses it. With a 504, by contrast, a proxy is waiting for a response from the backend server.
Most common causes
- A slow or unstable internet connection.
- Uploading a large file that takes longer than the server's limit.
- A pre-opened connection that stays idle.
- A timeout set too low on the server or proxy.
What you can do as a visitor
- Retry the request; a 408 is often transient.
- Check your connection with an internet speed test.
- Use a more stable network for file uploads.
What the site owner or developer should do
- Check client_body_timeout / header timeouts on the proxy.
- Upload large files in chunks or directly to storage (e.g. signed URLs).
- Monitor whether 408s come from specific networks or devices.
Impact on SEO and Google
Occasional 408s have no impact. If Googlebot gets them regularly, your server's limits are too strict.
Frequently asked questions
Does a 408 mean the server is overloaded?
Not necessarily. It means the request didn't arrive in time, and the cause may be on the client side.
What's the difference between 408 and 504?
408: the server is waiting on the client. 504: a proxy is waiting on the backend server.