Hi,
First of all, you must have a registered domain and a hostname already configured in some DNS, so you must access Issabel GUI from domain and not ip address, like:
https://myissabel.domain.com
You then must verify that both port 80 and 443 are opened/not blocked or filtered in any firewall, if you have the filrewall enabled in issabel, be sure to alllow those ports, or disable the firewall when doing the letsencrypt certificate retrieval.
Go to Security - HTTPS Certificate
Fill the form, follow the steps listed, there are not hard at all. The system will acquiere the certificate from letsencrypt and finish after 30 or a bit more seconds. If it fails, it is because ports are blocked or your DNS is not setup well.
Once you get the certificate, depending on the issabel-security version, you already migth have the certificate created in /etc/asterisk/keys/asterisk.pem
If you do not have it becuase your issabel-security package is not updated, you can create it with one command:
for A in `grep '^SSLCert' /etc/httpd/conf.d/ssl.conf | grep -v chain | awk '{print $2}'`; do cat \$A >>/etc/asterisk/keys/asterisk.pem
Then you can refer to /ect/asterisk/keys/asterisk.pem whenever the cert file confg is requiered, there is no need to specify a private key because it is contained in the same cert.
Best regards,
