Maintenance for the week of November 17:
• [COMPLETE] ESO Store and Account System for maintenance – November 17, 6:00AM EST (11:00 UTC) - 4:00PM EST (21:00 UTC)
• Xbox: NA and EU megaservers for maintenance – November 19, 4:00AM EST (9:00 UTC) - 12:00PM EST (17:00 UTC) https://forums.elderscrollsonline.com/en/discussion/685477
What specific error message are you getting when trying to log in?
You can perform a connection test on your Xbox One to see if there are any issues:
Press the [Menu] button on the controller.
Select Settings.
Select Network.
In the second column titled Current Network Stats, check the NAT status and confirm whether it is reading that your console is running on wireless or Ethernet correctly. The NAT should show as Open.
For troubleshooting a disconnect in your connection, select Troubleshooting and then Test Network Connection.
The NAT types can be one of the following:
OPEN: Can play games with any other NAT type.
MODERATE: Can play games with open or moderate NAT types.