Free tool

Explain this browser warning

A red screen, a crossed-out padlock, a code like NET::ERR_CERT_DATE_INVALID? Paste the message or its code: we tell you what it means, whether to worry, and what to do.

The text can be partial, in English or French, with or without accents. The small code under the message is the most precise.

Common

🔒 The search runs in your browser: what you type is not sent anywhere.

Four families of messages

NET::ERR_CERT_…

Certificate

The browser cannot confirm the site is who it claims to be. Often an expired certificate, sometimes your own clock.

Do not type anything sensitive until it is resolved.

ERR_CONNECTION_… · DNS_…

Connection

The browser cannot reach the server: name not found, server off, network cut.

No danger, just an outage (yours or the site's).

403 · 404 · 500 · 503

Server errors

The server answered, but with an error. From 400 to 499: the request (page missing, access denied). From 500: the server itself.

No danger for the visitor.

Red screen

Flagged site

Google or Microsoft considers the site dangerous: phishing or malware.

The only one that calls for turning back without hesitation.

Is it me or the site?

  1. Try another siteIf nothing works, the problem is your connection, your clock or your antivirus.
  2. Try another networkSwitch from Wi-Fi to mobile data: corporate and public networks filter a lot.
  3. Ask for an outside opinionOur down for everyone or just me? tool checks the site from our server, and our device clock check compares your device's time to the real one.

If you run the site, our SSL certificate, redirects & HTTPS and flagged as dangerous? tools show the problem from the outside, as your visitors see it.

Should I click “Proceed anyway”?

On a site where you only read, the risk is limited. On a site where you log in, pay or enter personal information: no. A certificate warning means you cannot be sure who is on the other end, which is exactly what a fraudster needs. And never bypass a red screen.