I found a solution to this problem myself. Here's what I did: I disconnected my desktop from the internet (from router) and reconnected but this time on my phone using the GSM network. Activating Vegas Pro and SaundForge went smoothly. Now I would like to listen to some proven tips on how to configure Vegas Pro so that it does not crash so often (because that was the reason for reinstalling the program).
@Janusz-Konefal as advised by @RogerS please post your different issue in a new thread as it won't be noticed in an unrelated thread, which was actually started by another user. Click your avatar (upper right corner) and choose New:Post. Thank you.
... side note on connecting to Magix in Poland. I am in Lublin, Poland and never had a problem. I just bought a Magix product where you have to activate and install online, and it went without any problems. My ISP is Orange and I have a fiber optic connection.