To focus on the relevant part of that, the Let’s Encrypt expiration e-mails are sent if Let’s Encrypt has not issued a new certificate with exactly the same names as the previous (expiring) certificate. Let’s Encrypt does not attempt to check whether the newly-issued certificate has been installed or is being used anywhere.
As @schoen said, Let’s Encrypt does not verify that your certificate is properly installed and functioning. All it does it check if one has been issued. If one has not been issued to replace an expiring certificate you will recieve an email.
Checking crt.sh (https://crt.sh/?q=cloud.rivard-international.com) I can see a new certificate was issued yesterday, November 6th, As a result an expiration email was not sent since your certificate was successfully renewed. You should reconfigure your webserver to use this new certificate.