4xx Client error
HTTP 417 Expectation Failed
The server can’t meet the expectation in the request’s Expect header. In practice it is a server or proxy that doesn’t support Expect: 100-continue.
//_01 Uptime checks
Is 417 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 417 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/
Up. The checker counts any answer below 500 as the site answering: a 417 comes from a server that is running.
//_02 Causes and fixes
Why you see 417 and what to do
Typical causes
- A client (such as curl or a .NET HTTP client) sending Expect: 100-continue to a server or proxy that rejects it.
If you run the site
- Have the client send the request without the Expect header; with curl, add -H "Expect:".
If you’re a visitor
- Nothing you can change in a browser.
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 417 mean?
The server can’t meet the expectation in the request’s Expect header. In practice it is a server or proxy that doesn’t support Expect: 100-continue.
Does an uptime monitor count 417 as down?
Down. It is outside the default 200–399 range, so a monitor reports an outage once a second check confirms it. If 417 is the answer you expect from that URL, add it to the monitor’s expected status codes.
Downtime is obsolete.
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