I was getting an A21 exception
This was similar to the exceptions here: https://community.developers.refinitiv.com/questions/26930/rfa7-not-connecting-to-ads.html
This was until I changed the code to use "GetDefPosition()" based upon another example that came with the RFA downloads.
The main difference here is that the network address has a "/net" suffix added.
Please update your tutorial code .