Hello
I followed the instruction here carefully
and after executing ./letsencrypt-auto command I entered my domain - and then I got this error
how to fix it and get the certificate ?
It seems like cPanel is interfering with the tls-sni-01 challenge.
You might have more luck with a guide more specific to cPanel, for example https://bitbucket.org/webstandardcss/lets-encrypt-for-cpanel-centos-6.x