1) Have you tried using the the TRtcClientModule component with the Call method and a TRtcResult component (standard event-driven way for calling remote functions) instead of using the Execute method?
Yes, I have.
2) Have you tried running the Client from a Debugger on an iOS device, to see what is going on?
No, It is quite difficult for me to debugging on iOS emulator.
And now I've moved from using remote function call to use TRtcDataProvider & TRtcClientRequest. It seems to work without any problems.
Thank you very much Danijel for your help.
Best Regards,
Kittipong Rungruangwat