It simply means the website you were trying to visit doesn’t have an up-to-date secure sockets layer (SSL) security certificate.
This certificate stops hackers from seeing or stealing any information transferred, including personal or financial data.
'Juice Jacking' Alert: Protect Your Smartphone from Hackers
"It establishes an encrypted connection between your web browser and the website you’re visiting," said the firm.
This is particularly vital when, for example, you're doing online banking.
The way you'll know that it's a SSL-protected site is that the web address begins with HTTPS, with the “s” standing for “secure.”
Or, there might be a little padlock symbol in the address bar.
How to browse the internet safely
Keep your internet cookies out of the hands of criminals
These tips will help keep your accounts safe from cookie thieves and your devices free from malicious software, says :
Multi-factor authentication (MFA) - makes it extremely difficult for a criminal to log into your accounts, even when they have your password and username
Watch out for phishing attempts and risky websites - Cookie-stealing malware often hops onto innocent devices through either phishing lures or through visiting untrustworthy sites
Clear your cache regularly - Make it a habit to clear your cache and browsing history often
Use a password manager - It's a vault for all your login information for your dozens of online accounts
HOW TO FIX IT
If you're 100% sure the website or page is safe, there are ways around the warning.
For starters, you could refresh the page - in case the error message is only a temporary issue.
Or, try closing the browser and reopening it.
HACK ALERT
But, be very wary when trying to use public Wi-Fi.
"Hackers often exploit public Wi-Fi because their routers are usually not as secure or well-maintained for security," said McAfee.
"Some public Wi-Fi networks might not support SSL connections altogether."
You should double-check you have the right website, as cybercrooks and scammers try to snare people through misspelled or alternative URLs to official versions.
Don't forget to keep your critical software and the operating system fully updated.
And, if you’ve tried all the troubleshooting tips and still see the error, the problem is probably from the site itself.
"You’ll have the option to 'proceed to the domain,' though we don’t recommend it," the firm added.
"The bottom line is that you take your chances anytime you ignore an error like this."