The module always logs a success result for requests (Input). Responses from cPanel (Output) may not result in success. If you don't receive a response, then you may have a log with an Input value but no corresponding Output.
The error check you removed from the module appears to be accurate. Blesta is unable to communicate with the server, or the credentials are incorrect. Make sure that the server Blesta is installed on meets the system requirements. If no outbound connections are being attempted, make sure you have curl available to php.
If you're still not able to find out where the problem lies, you can check if the module is throwing an exception. You will need to add a line of code to the module.
Open /components/modules/cpanel/cpanel.php and find:
$this->log($module_row->meta->host_name . "|listpkgs", null, "input", true);
Just below that is a catch statement:
catch (Exception $e) {
// API request failed
}
Update it to log the exception message:
catch (Exception $e) {
// API request failed
$this->log($module_row->meta->host_name, $e->getMessage() . " \n\n" . $e->getTraceAsString(), "output", false);
}
Then go to add/edit a cPanel package in Blesta. A request will be made to fetch the packages from cPanel. If an exception is thrown by the module, the module will now log an entry into the Module Logs table under [Tools] -> [Logs] that should give more insight into the problem.