The version of my client is (e.g. output of
certbot --version or
certbot-auto --version if you’re using Certbot):
[ec2-user@(snip) letsencrypt]$ /opt/letsencrypt/letsencrypt-auto --versionRequesting to rerun /opt/letsencrypt/letsencrypt-auto with root privileges…
https://sendy.amazinglybrilliant.com.au works for me, and for most other people. But occasionally I get emails saying that it doesn’t work. It uses a LetsEncrypt certificate.
One (relatively technical) user forwards one error from his Windows computer, which reads:
This site can’t provide a secure connection
sendy.amazinglybrilliant.com.au sent an invalid response.
Try running Windows Network Diagnostics.
Another sends a screenshot from mobile Safari, which says “sendy.amazinglybrilliant.com.au may be impersonation sendy.amazinglybrilliant.com.au to seal your personal or financial information. Safari warns you when a website has a certificate that is not valid.”
I can’t see anything wrong with the certificate, using a few online test websites. Many, many users are using it without any issue. But I’m not really very clever with this kind of thing. Have I messed something up?