Is it safe to click Proceed or Advanced?

Not on a page that asks for a password, card details, or personal information. If you must see a page that holds nothing sensitive and you know the cause, such as a test site you manage, it carries less risk. Some sites do not allow bypassing at all, which is intentional.

Why do I see it only on one network?

The network may interfere with secure connections. Public Wi-Fi often needs a sign-in page first, and some networks and security tools inspect secure traffic and present their own certificate. Try mobile data to see whether the warning disappears.

Why do I see it on every site at once?

That usually points to your device: a wrong date or time, outdated software, or security software that inspects secure traffic. Fix the clock first, then update the browser and system.

What do the codes such as ERR_CERT_DATE_INVALID mean?

The code names the problem. DATE_INVALID means the certificate looks expired or not yet valid, often because of your clock. AUTHORITY_INVALID means the issuer is not trusted. COMMON_NAME_INVALID means the certificate does not match the site's name.

I run a website and visitors see this. What do I do?

Check that the certificate has not expired, that it covers both the www and non-www names you use, and that the full certificate chain is installed. Turn on automatic renewal, and test the site from another network and device.

'Your Connection Is Not Private' Warning: What It Means and How to Fix It

Written by the Yorozuya IT editorial team, based in Japan. Last updated above. Menus, apps, and rules change, so check the date.

You click a link and a red or grey page appears: Your connection is not private. It can feel alarming, and in some cases it is a real warning. But very often the cause is something small on your side. The skill is to read the warning, find the cause, and know when to stop.

What the warning means

When you open a secure site, your browser checks a digital certificate that proves the site is who it claims to be, and that nobody can read the traffic in between. If that check fails, the browser warns you. The failure can come from three places:

Your device: the date or time is wrong, or the software is out of date.
Your network: a public Wi-Fi sign-in page, a school or office network, or a tool that inspects secure traffic.
The website: an expired certificate, a certificate for the wrong name, or one from an untrusted issuer.

Three causes of the not private warning: your date or time is wrong, the network interferes, or the website's certificate is bad

Step 1: Read the code

Under the warning, the browser shows a code. It tells you the reason.

Code (Chrome style)	What it often means	Where to look
ERR_CERT_DATE_INVALID	The certificate looks expired or not yet valid	Your date and time, or the site's renewal
ERR_CERT_AUTHORITY_INVALID	The issuer is not trusted	A network that inspects traffic, a self-made certificate, or old software
ERR_CERT_COMMON_NAME_INVALID	The certificate does not match the site name	A wrong address, or a site set-up error
ERR_CERT_REVOKED	The certificate was cancelled	The site; wait or contact the owner

Firefox and Safari word it differently, such as "Warning: Potential Security Risk Ahead" or "This Connection Is Not Private", but the same causes apply.

Step 2: Fix your clock

A wrong date or time is the single most common cause. A certificate is valid only between two dates, so a device that thinks it is a different year makes valid certificates look expired.

Windows: Settings, Time and language, Date and time, and turn on Set time automatically.
Mac: System Settings, General, Date and Time, and set it to update automatically.
Phone: turn on automatic date and time in the settings.

Reload the page. If the warning is gone, that was the cause. A drained or replaced battery on an old computer can reset the clock, so check it after a long shutdown.

Step 3: Try another network

If only one network shows the warning, the network is the problem.

Public Wi-Fi: hotels, cafes, and airports often need you to open a sign-in page before secure sites work. Open a plain http:// page, such as http://neverssl.com, to trigger it.
Switch to mobile data and reload. If the warning disappears, the first network was interfering.
Work or school networks may inspect secure traffic with their own certificate. Ask your IT team if you see the warning there.

Step 4: Update and try a clean start

Update the browser and the operating system. Old software may not trust newer certificate issuers.
Try a private or incognito window, or another browser. This shows whether an extension or saved data is interfering.
Check security software that scans secure connections. It can cause the warning on many sites. Check its settings rather than switching it off.
Restart the device, and try again.

When it really is the site

If the warning appears on one site, on every device and network, the site has a problem. It may have forgotten to renew a certificate, or it uses a certificate for a different name. This is not your fault, and there is little to fix on your side.

Do not enter passwords or card details while the warning shows.
Tell the site owner through another channel, such as email or social media.
Come back later, since owners usually fix it quickly.
Check that you typed the right address. A lookalike address is a classic phishing trick. If you got to the site from a message, see what to do if you clicked a phishing link.

If it is your own website

Visitors seeing this on your site is a sign to act.

Check the certificate's expiry date and renew it.
Make sure it covers every name you use, such as example.com and www.example.com.
Install the full certificate chain, not only your own certificate.
Turn on automatic renewal so it does not lapse.
Test from another network and device, and with an online certificate checker.
Set a reminder a few weeks before expiry, in case automation fails.

Common mistakes

Clicking Proceed on a page that asks for a password.
Ignoring a wrong clock and chasing other causes.
Switching off all security software to make the warning go away.
Using public Wi-Fi for banking while the warning shows.
Assuming the site is hacked when the cause is local.

A 30-second check habit

Look at the address to be sure it is the site you meant.
Look at the code under the warning.
Check the clock, then try mobile data.
If it still shows, stop and tell the owner.

Quick checklist

Read the error code.
Set date and time to automatic.
Try mobile data or another network, and open a plain http page on public Wi-Fi.
Update the browser and system.
Never proceed on pages that ask for passwords or payments.

Save this cheat sheet

Cheat sheet: fixing the your connection is not private warning

Screenshot this or save the image. It is the short version of the guide, and it is easier to find in a hurry than a web page.