We're aware of an issue with Gauntlet where this happens. Since it's happening in Champions games, it's possible you hit the security limits. Did you play a lot of games over a short period of time? If so, you'll need to wait about 24 hours for that to expire.
If you weren't playing a lot of matches, try power cycling your modem/router and hard restarting your console with these steps:
- Unplug your modem/router for 2 minutes
- Hold down the power button on your console until it turns off
- Plug in your modem/router and make sure it's online
- Power on your console and try playing again
Let me know if this helps or not. Thanks!