Hi,
Please share the URL you are using in SOAP UI. I faced 500 internal server error because of wrong URL
http://<host name> : <port name> /XISOAPAdapter/MessageServlet?channel=<Business comoonent name> : <channel name>
Use this URL.
To be sure of firewall issue... From the system you are trying to PUSH the soap message. In that system
1. Open CMD (command prompt)
2. ping <ip address of your PI system> OR ping <serverpi>.xyz.com
if the ping result is without any loss then no network issue it is then either because of URL or sender channel configuration mistake...
Regards
Vikas Singh