This looks as if your account is not NFA compliant.

Probably your trades are not executed on the real market, but on a virtual market simulated by the MT4 server. In that case you must NOT set the NFA flag. You can find out easily: Try to close the trade manually. If that is possible, your account is not NFA compliant and you must not set the NFA flag. But you need to set Hedge to 0 or 4.