Couldn’t open socket connection to server. Error (110): Connection timed out NuSoap

I am using NuSOAP – SOAP Toolkit for PHP to send SOAP request in WordPress Site. But every time I see following error

wsdl error: Getting http://(ServerIPAdress):(Port)/OUGWar/workflow_soap – HTTP ERROR: Couldn’t open socket connection to server, Error (110): Connection Times out

I have tried following solution by searching on the internet and specifically on Stack Overflow but still I am not able to resolve this issue.

Things I have tried so far:

1. Increased the Timeout Time from the API
2. Open the required ports in my hosting server
3. Allowed the Server IP in my Hosting Firewall (mean server IP is whitelisted in my hosting firewall where I am sending SOAP Request)
4. Checked through phpinfo(); that fsockopen(); function is enabled, Safemode is off and all required functions for the api is enabled like fopen(); and other
5. Verified the WSDL sample with SOAP UI and Its working perfectly there so no problem in creating structure of WSDL Request and calling

Kindly help me if I am still missing something.