For all other possibilities you need to check with your administrator the PHP log.
-If you received an empty response from your SugarCRM installation (instead of XML response), so, we think that there is something wrong in your SugarCRM installation or configuration. Please note that the proper functioning of our extension depends on the SugarCRM response, installation and configuration.
Unfortunately, we do not provide the support for SugarCRM. Please see with your administrator or web hoster to fix this issue.