This is the speed my phone is running and I still continue to get the notification saying...

Yes. Also, if lock the phone while the game is running in the main menu. I will receive a notification saying it is my turn when someone makes a move. However, if i unlock the phone it doesn't refresh. If i tap the notification, it relaunches the app and
I can start playing. Or if I am not quick enough and the notification on the top vanishes, I need to relaunch the app manually.

Another issue is, sometimes relaunching the app still doesn't refresh it. I need to tap on the invite and enter the match directly, skipping the main menu.

Just confirming that I did need to update, sorry about that. However the issue still persists. I’m now on 15.0.2 and my phone is iPhone 12 mini. Xbox app still says my phone has disabled notifications but there is no option I can find to enable them. All my other apps have notifications just fine. Thanks

Even using a wired connected what Steelwand said is still gonna be true. I use a wired connection for my One X and when I check detailed statistics (basically a speed test) my speeds are substantially lower than if I run a speed test on my phone using
the closest server.

Thanks for the help.

I tried all that and still get the notification. I've also logged in on a different phone and get the same notification so it's definitely something to do with my account. I called MS and they were no help at all.

Our engineers and developers are actively continuing to work to resolve the issue causing some members to have problems signing in to Xbox Live. Stay tuned, and thanks for your patience.

Want to get notified when this feature is back online?

We will only use the phone number that you provide to notify you when the service or app is back up and running. After we send the notification you requested, we will delete your phone number from our Xbox Live SMS notification system.