Failed to connect to matchmaking servers [PC]

I was able to determine this morning that my issue was due to host firewall blocking teredo traffic on port 3544. My firewall has a default rule to block inbound and outbound traffic on that port. I disabled that firewall rule and was able to connect with no problem. Even though i had setup port forwarding on my router the firewall was killing the traffic before it ever left my computer.

Running “netsh interface Teredo show state” in command prompt gave me two different status messages. When teredo type=client, behind the firewall you will never get status on NAT, NAT Special Behaviour, Local Mapping, and External NAT Mapping.

I didn’t find out about the error until I switched my Teredo type to enterprise based off a recommendation from this thread. [Windows 10] Fix for "Failed to reach matchmaking servers"
While I was behind the firewall “netsh interface Teredo show state” gave me “teredo primary server unreachable over UDP” errors.

Google search led me to the port 3544 issue.
https://technet.microsoft.com/en-us/library/ee844188(v=ws.10).aspx
"If the Teredo state is offline and the error state is Teredo server is unreachable over UDP, UDP port 3544 traffic may be blocked somewhere between the DirectAccess client and the DirectAccess server due to the following:

  • A third-party host firewall that is running on the DirectAccess client.
  • An intermediate router or network firewall between the DirectAccess client and the DirectAccess server. It is a common practice in organizations to block unexpected UDP traffic with their Internet firewalls"

All this to say check your firewall rules and see if the traffic is being blocked on UDP port 3544. Worked for me and I hope it works for you.

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