If you get an installation error when trying to install Let’s Encrypt SSL in cPanel, try the following steps:
DNS error 400
Check that your domain name is pointed to the server. You can use a free service such as IntoDNS or DNSChecker to check your nameservers and that your domain name is pointed to the right IP address.
If you are certain your domain name is pointed correctly, try to issue the SSL certificate again, however, uncheck the mail.yourdomain.com option.
Invalid response error
This could mean that your domain name is pointed to a different server or you have some blocking rules set in your .htaccess file. Try renaming your .htaccess file and then re-issuing the SSL certificate.
Error code 429
Although this is a rare error, it can happen and means that too many attempts have been made to install an SSL certificate. In this instance, you will need to wait 7 days before trying to install the certificate again.
