Step by step tutorial for beginner EA for moving average and ADX indicator

[ericmslim51968280982]

I complete coding the step-by-steo EA of moving average for beginner (url:https://www.mql5.com/en/articles/100) and compiled, show Ok.

But when testing in on my Demo account, it inccurs following error.  Please anyone can help.

The whole situation took place like below:

After using debug I found that when the code run up to the following place(line 261), it jumps to error line and showing the following error message. 

"The Sell Order request could not be completed -error:4752."  I would be much appreciated if anybody can help, thank.

My EA Error at Line 261  OrderSend(mrequest,mresult);

         OrderSend(mrequest,mresult);

         // get the result code

         if(mresult.retcode==10009 || mresult.retcode==10008) //Request is completed or  placed

           {

            Alert("A Sell Order has been successfully placed with Ticket#:",mresult.order,"!!");

           }

         else

           {

            Alert("The Sell Order request could not be completed -error:",GetLastError());

            ResetLastError();

            return;

           }

        }

The Sell Order request could not be completed -error:4752, after checking the MQL5 Reference I notice that 

4752 ERR_TRADE_DISABLED   Wrong trade property ID and 

4756 ERR_TRADE_SEND_FAILED  Trade Request Sending Failed (sometime it shows error 4756)

When I rebug, Code run upto above area, it runs into "Alert("The Sell Order request could not be completed -error:",GetLastError());

            ResetLastError();    return; 

and activate alert message "The Sell Order request could not be completed  code 4756"   (meaning 4756 ERR_TRADE_SEND_FAILED  Trade Request Sending Failed

according to MQL5 Reference.  Please help, thank.