On this page 6 sections
Is the 503 from the proxy or the site?
| Test | Result | It's the... |
|---|---|---|
| Load the target in a browser without the proxy | Also 503 | Site: it is down or overloaded for everyone |
Load another site through the same proxy (for example https://api.ipify.org) | Works | Site: the proxy is fine |
| Load the target through a new exit IP or another country | Works | Site, rate-limiting or blocking that IP or region |
| Every target through the proxy returns 503 in the same format | Proxy |
A 503 from the proxy side usually means the proxy can't serve that request right now, for example when no exit is available for a very narrow location. On ProxyField, the gateway's answer in that case is 502 Bad Gateway (ProxyField: temporary error. Try again in a few seconds.), and its answer when no traffic is left is 402 Payment Required (ProxyField: no traffic left. Top up at https://proxyfield.io). The dashboard shows real-time usage and remaining gigabytes, so check the balance first.
How to fix a proxy error 503
- Honor
Retry-After. If the header is present, don't send another request to that host before the time it gives. - Back off. Without the header, wait a few seconds, then double the wait after each 503 up to a cap. A queue of instant retries keeps an overloaded server down longer.
- Lower concurrency on that site. 503s that rise with your request rate mean the site, or a rule on it, can't take your volume.
- Retry through another exit IP. On per-request rotation, each retry already uses a new IP; if one IP or region gets 503s and another doesn't, the site is throttling that IP or region.
- Widen a narrow location. If you target a small city and see proxy-side 503s, try the region or the whole country; ProxyField targets country, region and city.
- Check the response body. A CAPTCHA or "unusual traffic" page inside a 503 means a bot block: fix headers, use a real browser where the site needs JavaScript, and slow down, as in 403 Forbidden when scraping.
- Wait out real outages. If the site is down for everyone, nothing on your side fixes it.
The retry example on 502 Bad Gateway and 504 Gateway Timeout retries 503 too and honors Retry-After. In Scrapy, 503 is in the default retry list; add AutoThrottle and a download delay (Scrapy).
503 vs 429 vs 502 and 504
| Code | What it says | What to do |
|---|---|---|
| 429 Too Many Requests | You personally are over a rate limit | Slow down; see 429 Too Many Requests |
| 503 Service Unavailable | The server can't take requests right now | Wait, then retry slower |
| 502 Bad Gateway | A gateway got an invalid answer from the server behind it | Retry from a new IP |
| 504 Gateway Timeout | A gateway got no answer in time | Retry with a longer timeout |
A Cloudflare-branded 503 page means the site's server behind Cloudflare is unavailable; see Cloudflare error codes explained.
Seeing 503 as a visitor
Reload after a minute or two. If the site still answers 503, it is likely down or in maintenance; check its status page or social accounts. If only your connection gets it, turn off your VPN or proxy and try again: some sites answer shared VPN traffic with 503.
Proxy Error 503 Service Unavailable FAQ
What does proxy error 503 mean?
ProxyField residential proxies run at a 99.6% success rate, according to our service data, and proxy error 503 means the server that answered can't handle the request right now. Test it with 2 requests, the target without the proxy and another site through the proxy: if the target fails without the proxy too, the site is overloaded or in maintenance, and if every site fails through the proxy, the proxy side is the problem.
Is a 503 error my fault?
Usually not: it is a server-side status. It can be partly yours when your request rate overloads a site or triggers a rule that answers bots with 503; slowing down then makes it go away.
How long does a 503 error last?
As long as the overload or maintenance lasts, from seconds to hours. If the response has Retry-After, that is the server's own estimate; wait at least that long.
Should I retry a 503 response?
Yes, after a wait: honor Retry-After, or back off exponentially without it. Retry only idempotent requests such as GET.
Why do I get 503 only when scraping?
Some sites answer suspected bots with 503 instead of 403, often with a CAPTCHA page in the body. Treat it as you would a block: browser-like headers, a real browser where JavaScript is needed and a slower pace first, and another IP type only after that.
What is the difference between 503 and 429?
A 429 says you sent too many requests; a 503 says the server can't take requests from anyone right now. In both cases, wait and come back slower.
How does 503 differ from 502 and 504?
A 503 comes from a server that is up but refusing work for now. A 502 or 504 comes from a gateway that couldn't get a valid or timely answer from the server behind it.
Can a proxy fix a 503 error?
Only when the site is throttling your IP or region: a retry from another exit IP or country then passes. When the site is down or in maintenance, no proxy helps.