ZendFramework应用程序上的TCP错误

My app runs okay on local dev machine and two other cloud servers.

But on a client's cloud its under firewall so having the TCP error:

 PHP Fatal error:  
 Uncaught exception 'Zend_Http_Client_Adapter_Exception' 
 with message 'Unable to Connect to tcp://mydomain.com:80. 
 Error #110: Connection timed out' in /path/to/proj/library/Zend/Http/Client/Adapter/Socket.php:235
 Stack trace:
 #0 /path/to/proj/library/Zend/Http/Client.php(973): Zend_Http_Client_Adapter_Socket->connect('mydomain.com', 80, false)
 #1 /path/to/proj/library/Zend/Rest/Client.php(137): Zend_Http_Client->request('GET')
 #2 /path/to/proj/library/Rbs/DataSource/Dao/Service.php(17): Zend_Rest_Client->restGet('hrm/api/employe...', Array)
 #3 /path/to/proj/Application/Models/EmployeeManager.php(13): Rbs_DataSource_Dao_Service->fetch('hrm/api/employe...', Array)
 #4 /path/to/proj/Application/Models/Employee.php(16): Application_Models_EmployeeManager->fetch('hrm/api/employe...')
 #5 /path/to/proj/library/Rbs/Controller/Action/Base.php(69): Application_Models_Employee->fetch('hrm/api/employe...')
 #6 /path/to/proj/libr in /path/to/proj/library/Zend/Http/Client/Adapter/Socket.php on line 235, referer: http://mydomain.com/hrm/

So, the question is how to get past the firewall and make the App working for these requests?