5xx Server error
HTTP 511 Network Authentication Required
The client needs to authenticate to get network access. It comes from captive portals, the sign-in pages of hotel, airport and café Wi-Fi, that intercept traffic until you sign in. Websites themselves don’t send it.
Defined in RFC 6585, section 6(opens in a new tab)
//_01 Uptime checks
Is 511 up or down for a monitor?
Uptimecheck HTTP monitor
Default settings
Down. It is outside the default 200–399 range, so a monitor reports an outage once a second check confirms it. If 511 is the answer you expect from that URL, add it to the monitor’s expected status codes.
Is it down? checker
Free, at /is-it-down/
Down. A 5xx means the server, or something in front of it, failed to answer.
//_02 Causes and fixes
Why you see 511 and what to do
Typical causes
- A Wi-Fi network that asks you to sign in or accept terms first.
If you run the site
- Nothing to fix on your site: it comes from the visitor’s network.
If you’re a visitor
- Open any page in the browser to get the network’s sign-in page, and sign in.
Know the moment your site stops answering as it should
An Uptimecheck monitor requests your page as often as every minute, checks the status code against the ones you expect, confirms a failure with a second check and then alerts you.
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Questions
What does HTTP 511 mean?
The client needs to authenticate to get network access. It comes from captive portals, the sign-in pages of hotel, airport and café Wi-Fi, that intercept traffic until you sign in. Websites themselves don’t send it.
Does an uptime monitor count 511 as down?
Down. It is outside the default 200–399 range, so a monitor reports an outage once a second check confirms it. If 511 is the answer you expect from that URL, add it to the monitor’s expected status codes.
Downtime is obsolete.
Set up your first monitor in under a minute, or look around the live demo first.
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