When you are trying to implement a transport of request via STMS, you can get an error message like “RFC Communication error with system/destination” with a popoup screen, then you need to check the below screen to solve the issue…

PopUp message should be like this ;

Then you need to logon Transport Domain System’s Client 000 and go to transaction STMS

Open the following screen with the below steps ;

STMS –> System Overview –> Double click the related SAP system which gives the error –> Goto “Communication” tab

You need to check the “Instance Number” area, probably this area is empty, if yes, then you need to edit (Ctrl+F1) the screen and insert the instance no information (If its a standart installation then this value will be “00” ) to related area and save it.

Now you can try it again…