There are several possible reasons why this might be. First of all, try the following:
- Please check your network settings. There is a possibility your network connection is not fast enough.
- Your NAT settings can also cause connection problems. In your Xbox One network settings, check your NAT settings are set to "Open."
- Connection problems may occur if your region settings don't match your current address. Check your Xbox One region settings match your current address.
If you are still experiencing problems in multiplayer mode, it is possible there is a server problem. Try waiting a while before attempting again.
If this does not solve the problem, please fill out a support form, clearly describing the issue.