There is a security warning on my smartphone, why is that?

When I use a smartphone, when I enter a site, I see a security warning below. Why is that?

Security Alert

The certificate on this website is invalid, which risks leaking your information. Do you still want to connect to the website?

2574 2017-03-11 Gentleman

A. 1

I watched it from time to time, but it works well even if I just use it kk

Gentleman 8 years ago 0

A. 2

Technically, sites that use the https protocol have their own certificates, which must be updated periodically.
Also, you need to get a certificate from an authorized institution.
This means that you are running an https site with a certificate that does not meet those requirements.
To put it simply, if it's a famous site, you can go in,
Otherwise, if you got the link via text or Kakao Talk,
It's better not to go in.

Gentleman 8 years ago 0

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