"RPC server is unavailable" error occurs when c# window application handle adobe Illustrator file opertaion

Question

Hi,

I have a c# wpf application that works on Adobe Illustrator file and uses SQL as DB.
I am getting "RPC server is unavailable" error while saving the illustrator file after doing series of operations.

And also the error occurs only in release mode, error doesn't occur when the application is run on the debug mode.
I checked rpcss service up and running. IPv6 service is running.
I have not made changes to firewall recently and the previous version of the application had run on the same settings successfully.
SQL DB operations seems to work fine even though it is connected remotely.

Please help on how to resolve the above issue.
Thanks.