If you are having any connection issues when attempting to play a co-op game, please try the following: 1. Software Conflicts Start by updating any anti-virus, anti-malware or personal firewall software that may be installed on your computer system. This includes your Windows Firewall, as well as updating the firmware for your home router. If updating these programs does not resolve the issue, you may need to temporarily shut-down the associated programs or bypass the router and establish a direct connection to your modem. You can also temporarily disable your anti-virus, anti-malware, firewalls, and any other applications that are affecting your network traffic before testing the game. If you can determine which application is configured too strictly, you can then add the appropriate exception or allowance to that application to allow Ubisoft and Assassin’s Creed: Unity to communicate freely on your local network. Internet Connection Sharing (ICS) and Virtual Private Networking (VPN) applications can also be conflicting with the game and you will want to disable these applications to try to resolve the issue. 2. Port Forwarding If it is not possible to shut-down your firewall, you will need to configure your router and/or firewall to forward the following network ports to your PC for the best possible connection: Assassin's Creed: Unity Co-op ports TCP: 80, 443 UDP: 3074 Ubisoft Launcher TCP: 80, 443, 13000, 14000, 14008 Directions for configuring network ports are specific to the software and hardware being used, and can be found by visiting the manufacturer's website. Please visit https://support.ubi.com/en-US/faqs/000024619 for more information. 3. Background Applications You may also encounter problems due to applications running in the background on your computer system. When playing Ubisoft games, please be sure to close all running background applications before starting your game. You can find the steps for this listed below. - Open your start menu and look for Run (Win XP), Start search (Win Vista), or Search programs and files (Win 7) - Delete anything on the Open line that you'll find there, and type in the word MSCONFIG and press the Enter key to bring up the system configuration utility - Look down the list of startup items (not the tab labeled Startup), and choose Selective Startup (if it is not already selected) (If you don't see this, make sure you've clicked on General, near the top of the window) - Once you've chosen Selective Startup, uncheck Load Startup Items - Once you're done here, click Apply & OK, and let it reboot your computer - Once restarted, make sure that any application that affects your local network is disabled Try running the game again. If the game loads and seems to be working, the problem is most likely related to one or more programs you have scheduled to load with Windows. You can then revert the settings back the way they were, and in a trial and error fashion, disable some programs using the startup tab (in the msconfig utility) to try to find the culprit. NOTE: Keep in mind that this is a temporary solution and any changes can be reverted by returning to the MSCONFIG utility and re-selecting Normal Startup 4. Restrictive Networking Environment There may also be certain restrictions set by your ISP or network administrator. If you continue to have trouble, please contact your ISP or network administrator for details on any specific restrictions on the previously mentioned network ports. 5. Local DNS If you are still having connection problems, you will want to try flushing your DNS and resetting your Windows hosts file. Flush DNS https://support.ubi.com/en-US/faqs/000024748 Reset hosts File http://support.microsoft.com/kb/972034 If you continue to have trouble, please submit a support ticket. Please include a full description of your problem, any error messages you may have received, and the following images: -Your port forwarding / virtual server configuration, which will allow us to view the ports and your network IP. -Your device's network configuration, showing the Manual (Static) IP you are using.