It seems that when the application starts, something is going on in debugging and it loses the connection in the middle of the connection, but then restores the connection, but it's too late. Thus, the application will simply burst, the connection will not work, because the application believes that it is doing it, so it is stuck in limbo, not knowing what to do.
Run the application outside of debugging and continue to do the same thing as when you received the error message, and see if you can recover this error.
If not, try disabling Wi-Fi / data as soon as you connect to the web service and see if you can recreate it, if so, then you know that this is due to the connection, not the code itself.