Well, this is nothing to do with structure I created in dialog.
I have used multiple nested multifield. So found error as tooManyCallsException for /libs/ui/components/coral/foundation/container/container.jsp
This error occurred for no of calling for multifield. There is a service as Apache Sling Main Servlet, where it ask for no of calls per request which is 1000 by default. I changed it to 10000 and it resolved this issue. Anyone else came accross this service? And where else it can impacted?