WWE has issued the following Network advisory today:
Thank you for signing up for WWE Network. We are working aggressively to address the login issue for Xbox users and expect to have it resolved by this Monday, March 3, if not sooner. You will be notified via email as soon as this issue is fixed. We apologize for this inconvenience and thank you for your patience.
In the meantime, please enjoy watching WWE Network on WWE.com, tablets, mobile phones or other connected devices.