Problem with SSL certificate?

Question

Digital certificates

I use a Let's Encrypt Authority X1 certificate on the site
Today, a friend said that he receives such a message in chrome and opera.
I tried to log in from different IPs, but everything is ok.
What could be the problem?

Answer 1

Maybe he has the wrong date on his computer. In such a case, the certificate could either have "expired" or not yet "be issued"

Answer 2

also checked, everything is fine, let your friend change the dns, update the browser, return the default browser settings (tls ssl etc)