One has nothing to do with the other.
Akeeba Panopticon uses the JSON API over the web to take backups.
Your CLI scripts go through the Joomla! CLI application.
Ask your host to help you with the error message you are getting. Since I don't have all the information, it could either be a misconfiguration of the PHP executable used in the CRON job (wrong path to the executable), or a permissions issue preventing the PHP executable from reading Joomla's cli/joomla.php file. Neither of these has anything to do with Panopticon.
					 
					
											
							Nicholas K. Dionysopoulos
Lead Developer and Director
🇬🇷Greek: native 🇬🇧English: excellent 🇫🇷French: basic • 🕐 My time zone is Europe / Athens 
Please keep in mind my timezone and cultural differences when reading my replies. Thank you!