If you're having trouble signing onto Xbox Live, you are not alone. Microsoft is aware of the issue and is "actively investigating," according to the official Xbox Support Twitter account. The Xbox Live status page at the time of writing does not report any issues.

Some of the reported issues from our forum include freezing when sending invites and being unable to sign back on.

UPDATE 1: Xbox Live status has updated with the below info.

XBOX LIVE Service
Users may experience difficulties with the following services:
Signing in to Xbox LIVE
7/8/2013 7:36:36 PM PDT:

Uh oh, are you having trouble connecting to Xbox LIVE? That's no good, but don't worry, because we are on it! We have our top engineers engaged and working on this issue. Thanks for staying patient while we work. We'll have another update for you in 30 minutes.

UPDATE 2:

XBOX LIVE Service
Users may experience difficulties with the following services:
Sending or receiving Beacon notifications
Viewing messages
Affecting the following LIVE Platforms:
Games for Windows LIVE
Windows 8
Xbox 360 Console
Xbox.com
7/8/2013 9:54:06 PM PDT:
We’re aware that our members are currently experiencing some trouble with the parties and messaging features on Xbox LIVE. That’s no good! We’re hard at work on this issue and we’ll update you on this situation in 30 minutes! Thanks for your patience.

If you see issues signing in & sending messages/invites, we're looking in to it. More info here: http://t.co/xympfK0NdE ^AC

— Xbox Support (1-5) (@XboxSupport) July 9, 2013

UPDATE 3:

Any issues with signing in and sending messages are now resolved. Thanks for sticking in there with us. Have fun online! ^AC

— Xbox Support (1-5) (@XboxSupport) July 9, 2013

Posted: Jul 08, 2013 9:35 pm
Related Forum: Xbox Forum

Source: http://www.thetechgame.com/Forums/t=5436137/xbox-live-is-down-keep-all-discussion-here.html