Hi Manish,
Please check the configuration once agian about the third party connection and the portal.
Also provide the "dev_server0" which under in directory /usr/sap/SID/J00/work and default trace which under in “/usr/sap/SID/J00/j2ee/cluster/server0/log" to analyze the issue. There is some other tool as well to check the issue using "httpwatch" log tool. But, mostly issue can be identified in dev_server0 or defalut trace".
Thanks,
Brindavan