Please try clearing your cache. 1. Restart your computer and launch Steam 2. From the Library section, right-click on the game and select Properties from the menu. 3. Select the Local files tab and click the Verify integrity of game files... button. 4. Steam will verify the game's files - this process may take several minutes. If the issue persists, please try rebooting your network equipment. Unplug your modem and router and leave them unplugged for at least a minute. Then, plug your modem back in and let it fully boot up, then your router. Then, try again. If the issue persists, then you will need to contact your ISP for further guidance on how to resolve this issue.