Hi Tenno,
If you're currently experiencing issues with accessing Warframe on your Xbox One, please hold tight. Our team is aware and is currently investigating the cause of this issue.
Thank you for your patience!
UPDATE: 5:15PM EDT
The Xbox Live Service Status page has been updated to reflect the current issue some Tenno are experiencing with Warframe. They have also added the option to be notified when this issue is resolved:
We will still be updating this thread with more news as it comes! 🙂