Hi there I too am having the same problem.I sent a ticket to support and they basically said the same as you have here, more likely anti virus or firewall. I removed AVG completely, turned off Windows firewall and windows defender, put all my internet settings to allow everything..... I literally have zero protection running but it still can't connect to the activation server. I must add that the internet is fine and even FSX can connect to update the Jeppson weather with no problem. I am open to any suggestions by anyone! Running Vista 64 bit as administrator with all security, antivirus uninstalled and/or off. PDMG 737 has been de-installed and re-installed several times with various settings and in the end with an exposed system but still no communication with activation server. Any ideas anyone?? Mark Bentley