The page uses a self signed https certificate. If you control the server for that website using LetsEncrypt's free certificates is one way to avoid the error. See https://letsencrypt.org/ for details It is possible to accept self signed certificates. First visit the page. On the "This connection is untrusted" page near the bottom tap on "I understand the Risks". Choose either "visit site" or "Add permanent exception" to access the website.