Watch the video:
Timestamps:
0:00 - Explanation
0:40 - Check server status
1:12 - See if it's just you
1:35 - Firewall or Antivirus
2:36 - WiFi
3:00 - Windows Firewall
Want to play Rainbow 6: Siege, but can’t because you’r receiving the 2-0x0000D00A error? Well, the reason is super simple: Your computer can’t communicate with the servers. By the end of this video you should either know if the server are down for maintenance or any other issue, or should have fixed any issues on your local internet connection or device that should allow you to play the game again.
Check Rainbow 6 Server status: https://rainbow6.ubisoft.com/status/