Multiplayer does not work [PC]

So this isn’t exactly a problem with Forza itself, its more to do with Windows 10. However, I have tried contacting regular Microsoft support several times being told that the issue would be forwarded to the Windows devs with no results after months of waiting (and Windows patches/updates). Multiplayer does not work on Forza Horizon 3 either for the EXACT same reason it doesn’t work in Motorsport 7.

Here’s the problem I’m having:
I go to access multiplayer, but the game comes up with an error:
FM7: “failed to retrieve server data”
FH3: “Failed to join session”

After extensively researching the issue (and contacting Windows support) it was discovered that it was an issue with Microsoft Teredo Tunneling Adapter. When I check the network in the Xbox app on PC, it literally says “Teredo is unable to qualify, this may impact your ability to play multiplayer games” I dug around on the internet for a fix to this problem. What I found was this: http://serverfault.com/questions/304555/teredo-error-failed-to-open-tunnel-adapter
However, this fix only lasts for 2 hours after rebooting… Strange right? Whats even dumber is that some of the hidden network devices talked about in the link, don’t exist on my PC. Instead there’s a ton of random WAN miniports. And on top of that, the Teredo Tunneling Pseudo-Interface doesn’t appear at all. Trying to update the Teredo Tunneling adapter doesn’t result in anything, just freezes up device manager and doesn’t close or cancel. The strangest part about all of this though, is that Halo 5: Forge works perfectly fine! What the heck right? Forza relies on Teredo, which doesn’t even work 99.9% of the time, its god awful.

Now, here’s what I hope to be gained from this: Forza tech support people contact Windows devs, who fix god dang Teredo, and multiplayer finally works without an extremely temporary fix of REBOOTING the PC and messing with device manager and command prompt. Or the Forza devs make multiplayer rely on something other than Windows’ half baked “networking” device, Teredo. Pls, I just want to play with my friends…

Useful info:
Windows 10 Home (x64) v1703, Build 15063.608
Intel Core i5-4670k
16GB DDR3
Geforce GTX 1070 ROG Strix
C: drive - 1TB 7200rpm HDD
E: drive (game install location, for both Forzas) 500GB 5400rpm HDD
Asus OEM M32 motherboard
My internet: 18Mbps down

I had a similar problem and finally could solve it. The main reasons are some anti Spyware and Win10 “optimizers” that disables, blocks various aspects that can all result in broken multiplayer for xbox live. So lets go through them all step by step.

  1. Follow the guide below, check if the teredo adapter and ip-helper service is setup and working, also ensure that the hostname is correctly set to “win10.ipv6.microsoft.com”. Verify all via “netsh interface Teredo show state”.
    http://support.xbox.com/en-US/xbox-on-windows/social/troubleshoot-party-chat

  2. Follow this guide to ensure the firewall is enabled and default rules are setup: http://support.xbox.com/en-US/xbox-on-windows/social/server-connectivity-xbox-app-displays-blocked
    2a) Enable and reset the windows 10 firewall to defaults via restore defaults in the firewall control panel option. (For some crazy reason the xbox live service will only correctly work if the firewall is set to On … even overriding the rules to allow all incoming connections, results in errors in the xbox app. I have no clue how this is even possible…)

  3. check your “/windows/system32/drivers/etc/host” file, make sure no windows.com site is listed there, by default the only entries are those:

  1. Make sure the xbox live services are set to default states (auto/manual) as described here: http://support.xbox.com/en-US/xbox-on-windows/social/server-connectivity-xbox-app-displays-blocked

  2. In your router add rules to forward all xbox live ports to your PC or open them. (Ignore port 80, its the default web port, which should not get a entry)
    http://support.xbox.com/en-US/xbox-one/networking/network-ports-used-xbox-live

If all works the command “netsh interface Teredo show state” should list some ip addresses at the last two lines and the “xbox app” should also show no errors via settings->network.

PS: If you get the error “disconnected from server” in FM7, than just try again a few times, this at least shows your general connection to xbox live servers are working.

I actually went more in depth in a follow up search of the internet this morning, and found a potential solution. I found an automated program that resets the entire Windows IPv6 stack. So far the xbox live connection has lasted longer than normal, and even survived putting my PC to sleep. Only time will tell if its permanent, or at least a lot longer lasting than the first solution I had. I feel like the firewall solution you have is a last resort option, if nothing else works

Check for teredo being enabled, it randomly got disabled for me a few days ago

http://support.xbox.com/en-GB/xbox-on-windows/social/troubleshoot-party-chat