A server error 492 indicates that the client has performed an HTTPS request to an HTTP server. This error occurs when a client attempts to use HTTPS (which is HTTP over an encrypted SSL or TLS connection) to communicate with a server that only supports unencrypted HTTP connections.
What causes error 492?
There are a few common causes of a 492 error:
- The client is trying to access an HTTP URL via HTTPS. For example, using https://www.example.com instead of http://www.example.com if the server only supports HTTP.
- The server only has HTTP enabled, not HTTPS. Many web servers require HTTPS to be manually enabled.
- The server is behind a proxy or load balancer that is configured for HTTP only.
- The client has cached an HTTP URL and is trying to use the cached URL over HTTPS.
Essentially, this error stems from a protocol mismatch between what the client expects (HTTPS) and what the server supports (HTTP). The client and server need to agree on using HTTPS or HTTP.
How to fix error 492
Here are some steps to resolve a 492 error:
- Check if the server supports HTTPS. Look for HTTPS binding settings, SSL certificates, etc. Enable HTTPS if it is not already enabled.
- If the server does not support HTTPS, switch the client request to use HTTP instead.
- Clear the browser cache and any saved URLs. Request the page again using HTTP or HTTPS as appropriate.
- If going through a proxy, check the proxy settings to ensure HTTPS traffic is allowed.
- Use tools like curl to verify HTTPS vs HTTP behavior:
Check HTTP:
curl -I http://example.com
Check HTTPS:
curl -I https://example.com
This can help determine if the issue is client-side or server-side.
Implications of a 492 error
Some key implications and side-effects of receiving a 492 status code include:
- The page won’t load, since the protocols are mismatched. Users will see a connection error.
- Any data sent between the client and server could potentially be exposed, since HTTPS encryption is not established.
- Browsers may display security warnings about the insecure connection.
- Features relying on HTTPS will fail, like geolocation, service workers, push notifications.
- SEO rankings may drop if Google detects the site redirecting HTTP to HTTPS incorrectly.
Overall, sites should seek to resolve 492 errors as soon as possible to restore full functionality and security.
Common troubleshooting questions
Here are answers to some frequently asked questions about troubleshooting error 492:
Why do I get a 492 error for one page but not another?
This points to inconsistent configuration. Some parts of the site may support HTTPS while others are still HTTP. Check all pages and confirm the site is using HTTPS consistently across all pages and resources.
Why does my site work locally but show 492 on live server?
Local servers are often configured differently than live sites. Ensure your live servers have HTTPS enabled with the proper SSL certificates installed. The configurations between local and live should match.
Why does my site work on desktop but mobile browser shows 492?
This can occur if the desktop site redirects HTTP to HTTPS but mobile does not. Mobile sites may be configured separately. Check that mobile pages properly redirect HTTP to HTTPS.
Why am I suddenly getting a 492 error?
Some possible reasons:
- The server HTTPS certificate expired. Renew the certificate.
- The web server was reconfigured to disable HTTPS inadvertently.
- A recent network change impacted HTTPS traffic, like new proxy or firewall rules.
Review any recent changes or events that could impact HTTPS connectivity.
How can I tell if a 492 error comes from the client or server side?
Use command line tools like curl to verify HTTPS and HTTP behavior:
curl -I https://example.com
If this fails, the issue is likely server-side. If curl succeeds, try from the client to determine if the issue is browser/client related.
How websites handle error 492
When servers encounter a 492 status code, they should be configured to handle it gracefully. Here are some common ways sites redirect and handle 492 errors:
Display a custom error page
Rather than showing a raw 492 status, sites can display a custom page explaining the error and providing guidance, like enabling cookies or trying again later.
Automatically redirect HTTP to HTTPS
Use a rewrite rule to redirect all HTTP requests to HTTPS. This helps avoid 492 errors entirely.
Redirect to the home page
Rather than attempt to load the mismatched HTTPS page, redirect back to the home page.
Try fetching the page again via HTTP
Detect the 492 status and automatically re-request the page via HTTP before redirecting.
Show alternate content
Display a cached static copy of the page or alternate content when 492 occurs.
Preventing error 492
The best way to prevent error 492 is to ensure consistent protocol usage between clients and servers. Here are some tips:
- Enable HTTPS across all site pages and configured consistently.
- Use HTTP redirection to redirect all HTTP requests to HTTPS.
- Check configuration on all load balancers, proxies, CDNs for HTTPS support.
- Don’t link HTTP and HTTPS resources on the same pages.
- Monitor mixed content warnings and fix any HTTP resources loaded on HTTPS pages.
- Cache busting to avoid cached HTTP-only URLs being used on HTTPS pages.
Taking proactive measures like these will help minimize error 492 occurrences.
Error 492 examples
Here are some sample 492 error messages from different servers and browsers:
Nginx
HTTP request to HTTPS port
Apache
HTTPS protocol error
Internet Explorer
SEC_E_ILLEGAL_MESSAGE
Google Chrome
ERR_INSECURE_RESPONSE
Curl
Rebuilt URL to: https://example.com/ Trying example.com... curl: (35) error:14077410:SSL routines:SSL23_GET_SERVER_HELLO:sslv3 alert handshake failure
The exact error message wording depends on the server and client, but will indicate some variation of an HTTPS request getting an HTTP response.
Summary
Error 492 means there is a mismatch between the HTTPS protocol expected by the client and HTTP provided by the server. Resolving this requires making sure HTTP and HTTPS usage is consistent across the entire site and server configuration. Proper redirect rules and preventing mixed HTTPS/HTTP content can help avoid these errors.
| Error Code | Meaning |
|---|---|
| 492 | Request to HTTPS server received HTTP response |
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| Fixes |
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Following HTTPS best practices across clients and servers can prevent error 492.