[SOLVED] Ghost Recon: Future Soldier coop invitation and connection issues

I wanted to reply in original question that has one of highest positions in google but it's locked from answers. [Help Needed] I can't connect to my friend/they can't connect to me when trying to do the coop campaign on Ghost Recon: Future Soldier

​

After quite a lot of hours waster looking for some solution or at least understand the problem I think I got it. As I bought Future Soldier sorely for co-op with my friend and it worked almost right away, when we could not connect again the next day I wanted to solve it. After many trials we were able to isolate issue to problems with certain servers.

Server that works: 185.38.21.82 ( Ubisoft International SAS )

Servers that were never able to connect GRFS coop game: 185.38.21.83185.38.21.84185.38.21.85

Solution:

1. Make sure you have only one network adapter running (any VPN, hamachi and others are causing "failed to connect to host".
2. Go to your firewall (either Windows Firewall or other you are using instead) and block IPs 185.38.21.83-85
3. Start Uplay and the game. If you want to verify that it worked correctly, you can verify that the game is connected to 185.38.21.82 using network traffic monitor like:
   https://www.nirsoft.net/utils/live_tcp_udp_watch.html
4. Now invitations and everything should work. It's slow, takes sometimes around 10-15 seconds to receive invitation but then it works.

It seems like other Ubisoft servers are not handling connections properly, only when both players are connected to proper server it starts to work. It also seems that either Uplay or the game itself is checking server response so blocking other IPs causes game to load the only one we left not blocked. This way both players can safely connect to the same server which handles co-op properly. Don't ask me how we found this solution.

Some facts:

1. Removing friends from Uplay does not matter.
2. Uplay has to be running to see friend status properly in game.
3. Fetching list of users takes some time. Just type your friend name in search box and wait around half a minute, it will show up always. Invitations also take around half a minute.
4. Restarting Uplay, game, computer etc does not change anything besides possibility that this time you may connect to proper server. That's why in our case game was connecting sometimes a few times in a row (working server has less latency) and sometimes no matter how much we try it was not connecting (other servers had better latency and those did not handle the game).

I wanted to play Ghost Recon many years ago but somehow I could not get it when first ones were out. Recently I wanted to play GRAW and GRAW2 but those don't work anymore, you can't even buy them on Ubisoft store. Future Soldier was oldest one I picked and gameplay is... ok. Only responsiveness and controls aged a bit but the game looks quite amazing.

I'm going to post this solution also in different high results from google so others can finally enjoy this game with their friends. I'm sure many of you resigned from co-op experience just because of server errors. It's not guaranteed that it will work forever, IPs may change, server configurations may change. Anyways, it was quite stable recently, I'll maybe update this topic when we test it a bit more. Most important is that we were able to rule out different scenarios that did not matter.

One more thing to check again would be trying out running it with different server but also blocking other ones to make sure you only have connection to one of them. I've seen that game is actually connecting to two different Ubisoft servers but in cases when we connected to the same 83-85 servers, it did not work as well. It only worked with connection through 82.