If a brand-new Xbox account can't connect to Xbox Live, check these categories:
Account & Subscription Issues
Activation Pending: Complete setup at account.xbox.com or on the console.
Suspension/Ban: Check email for enforcement notifications; appeal via enforcement.xbox.com.
Privacy Settings: Go to Settings > Account > Privacy & Online Safety > Xbox Live Privacy > View Details > Communication & Multiplayer and ensure "You can play online games" is set to Allow.
Missing Gold Subscription: Online multiplayer requires Xbox Live Gold or Game Pass Ultimate. Verify subscription status in Settings > Account > Subscriptions.
Region Mismatch: Account region must match your physical location and payment method.
Network & Hardware Troubleshooting
Test Connection:Settings > General > Network Settings > Test Network Connection.
Restart Equipment: Power cycle modem, router, and console (unplug 30 seconds).