Welcome to the Let's Encrypt Community! 
That error, when coming from Let's Encrypt, means that a Let's Encrypt validation server can't acquire the challenge file from your server. Please post the complete error message, verbatim, as it contains more information (e.g. primary versus secondary validation failure).
Also, you should upgrade to CertSage 1.4.2 since I fixed some timing issues in that version caused by changes made by Let's Encrypt.
Additionally, based on your previous thread, your .htaccess file(s) might be getting in the way, which sounds strange to me given that LiteSpeed is your webserver, not Apache. Creating a test file inside the /.well-known/acme-challenge/ directory inside the webroot directory for xensi.com (where certsage.php is currently located) then ensuring that said file is accessible from the public internet (e.g. from you smartphone not connected to WiFi) can help address this problem.
Depending upon what your cPanel allows, you can probably certify all of these domain names under a single certificate using CertSage:
autodiscover.xensi.com
cpanel.xensi.com
cpcalendars.xensi.com
cpcontacts.xensi.com
xensi.com
mail.xensi.com
webdisk.xensi.com
webmail.xensi.com
www.xensi.com