Including letsencrypt cert.pem

For some installations, you may need to also include the cert.pem contents into your certificate chain to avoid handshake errors. You will then have 4 certificates in your domain.com.pem file. Be sure the order is as follows: cert.pem, privkey.pem, isgrootx1.pem, then letsencryptauthorityx3.pem

If you moved all certs to a single directry, you may combine them using the following command in a *nix operating system.

cat ./cert.pem ./privkey.pem ./letsencryptauthorityx3.pem ./isrgrootx1.pem > mydomain.com.pem