I am on Windows 10 on both PCs with the Ultimate Collection on both each with a valid license I bought. Both computers can play campaign and skirmish games.
I was able to play RA3 in coop with my friend through internet but I am having problem playing with my son on my LAN. Both Network and Online (through C&C online) have issues. Network I cannot see the other player. Online I can see the players and each can host and join the other game but I get the Error connecting 1-2 problem when launching.
I tried the common solutions:
Solution 1: Not applicable since I bought two "The Ultimate Collection bundle".
Solution 2: Not applicable for RA3.
Solution 3: I can play with my friend on the internet so I have no firewall issue with C&C:Online.
Solution 4: I am using my LAN IP (192.168.x.x) in Network settings. I am not using Hamachi, Tunngle or similar services.
Solution 5a: Not applicable for RA3.
Solution 5b: Tried this but it does not help.
Solution 6: I don't want to reduce my LAN security by opening DMZ.
Another post suggested using a VPN:
Solution 7: I also tried ProtonVPN one the game hosting PC and that did not help either. I am getting the Error connecting 1-2 message.
Is there a way to troubleshoot this? I could not find any logs with detailed error. Anyone can tell me where they are?