If a website certificate is expired, the browser will display a message that the page the user wants to visit is insecure.
Source: Russia creates its own TLS certificate authority to bypass sanctions
DEEP STATE WATCHDAWGS™©® NEWS & MEDIA SHARING GOVERNMENT OVERSIGHT ORGANIZATION
NEWS & MEDIA SHARING, GOVERNMENT OVERSIGHT & PATRIOTIC AMERICAN ACTIVISM ORGANIZATION/ASSOCIATION CORP. INC.
If a website certificate is expired, the browser will display a message that the page the user wants to visit is insecure.
Source: Russia creates its own TLS certificate authority to bypass sanctions