Hi Ppushkar2001 and welcome!
One important question for you: is the new B server site URL in your local intranet or not? Look at the settings in the status bar for your browser and see if it says Internet or Local Intranet or Trusted Sites. If it's in Internet, try adding the new URL to yoru local intranet via the Tools->Settings->Security tab. If it's in Trusted Sites, remove it.
Not sure this will fix it, but it's the first thing to verify. Local Intranet is important because that ensures Domain Trust which is the default security model for InfoPath forms.
Good luck!