Why do I get a cell phone security alert?

pu1. I saw it sometimes, but it works well even if I just use it

2017-12-12

OK

pu2. Technically, the site that uses the https protocol has its own certificate, which needs to be updated periodically. Also, the certificate must be issued by an authorized institution. It means that we are running an https site with a certificate that does not meet those requirements. Simply put, if it's a famous site, you can go in, but if it's not and you've received a link through text or Kakao Talk, you shouldn't go in.

2017-12-12

OK