I have found that the situation is due to the fact that the listening ports of each service I modified. Normally inside the internal network I didn’t need to specify the port, only when coming from the outside, but I have added the port followed by the IP of the server, as well as in the SQL instance and I was able to establish the connection.
Thank you both very much for your valuable comments, indeed as recommended by @dal8moc , it is a safer way to use RDP.