Will a website fail to open if no SSL certificate is installed?

A website can still be accessed via the HTTP protocol without an SSL certificate installed, but modern browsers typically mark it as Not Secure, and some functions may be restricted.

If a website enforces HTTPS but has no SSL certificate configured, a connection error (such as ERR_CONNECTION_CLOSED) will be triggered when users visit it, making the page inaccessible.

It is recommended to install an SSL certificate to secure data transmission and prevent access exceptions.