We are aware some users are experiencing this issue and the matter has been forwarded over to Studio.
When updates are available you can always review the update notes here Ghosts Title Update and Hot Fix Notes (7/1/14)
Regarding connection, please be sure you have opened the correct ports for Xbox One Xbox Network Ports | Xbox One Network Ports | Xbox Live Network Ports - Xbox.com
Additionally, please try the following:
You can always check online services status here http://www.callofduty.com/ghosts/status
Currently the status is at Defcon 4 so you may experience intermittent issues with connecting to the server.
You may wish to check Xbox Live service status as well Xbox Live Service Status - Xbox.com
If online services are fully operational and you are still unable to connect, you may want to try the following.
- Reboot your router.
- Restart your system.
- Try using a wired connection in order to sustain the connection quality.
- To help identify if there is an issue with the router or blocked ports, try connecting directly through the modem.
- Establish a static IP address and port forward.
Should you have any questions on how to port forward, please contact your ISP or the router manufacturer.