Xbox: You receive a communication error (4920) when using a direct connection to Xbox Live (817631)

SYMPTOMS

Your Xbox console is connected directly to your modem. When you try to connect to Xbox Live, you receive the following error message:

The Xbox Live service cannot be contacted or is not responding. Please try again later or visit www.xbox.com/live for more information.

Note The error message in this article applies to version 4920 of the Xbox Dashboard. If you use a different version of the Xbox Dashboard, you may receive a similar, but different, error message.
To find the version number of the Xbox Dashboard, follow these steps:

On the Main Menu screen, press the directional pad (D-pad) up or down to select Settings, and then press the A button.
On the Settings screen, press the D-pad up or down to select System Info, and then press the A button.
The kernel version and the Dashboard version appear on the System Info screen. For example you may receive the following information on the System Info screen:

D:1.00.4920.01

This example illustrates version 4920 of the Xbox Dashboard.

THINGS TO TRY

Power-cycle the modem: Turn off the modem, wait one to two minutes after the lights on the modem turn off, and then turn the modem back on.
Important You must leave the Xbox console connected to the modem while you turn the modem off and on.
Note Most modems do not have on/off switches. You may have to unplug the modem from the power outlet and then again plug the modem in to power-cycle the modem.
Your Internet service provider (ISP) may only allow network devices that have a specific media access control (MAC) address and a specific host name, such as the MAC address and host name of your computer, to access the Internet. To determine whether this constraint may cause the problem, configure the Xbox console to use the MAC address and host name of your computer:
1. On your computer, click Start, click Run, type cmd, and then click OK.
  Note For Microsoft Windows 98, instead type command in the Run dialog box.
2. At the command prompt, type the following command:
  ipconfig /all
  The MAC address of the computer is displayed next to physical address.
3. Type the MAC address in the Xbox Dashboard:
  1. Remove any disc from the disc tray, and then turn the Xbox console on.
  2. On the Main Menu screen, press the directional pad (D-pad) up or down to select Settings, and then press the A button.
  3. On the Settings screen, press the directional pad (D-pad) up or down to select Network Settings, and then press the A button.
  4. On the Network Settings screen, press the D-pad down to select Advanced, and then press the A button.
  5. On the Advanced screen, press the D-pad down to select MAC Address, and then press the A button.
  6. Use the on-screen keyboard to type the MAC address that you obtained in step 2-b, select Done, and then press the A button.
    Note Do not include any dashes in the MAC address.
Try to connect to Xbox Live again.
If you still cannot connect to Xbox Live, obtain the connection error codes:
1. On the Main Menu screen in the Xbox Dashboard, press the directional pad (D-pad) up or down to select Settings, and then press the A button.
2. On the Settings screen, press the D-pad down to select Network Settings, and then press the A button.
3. On the Network Settings screen, press the D-pad down to select Connect, and then press the A button to view the Connect Status screen and to test the connection to Xbox Live.
4. On the Connect Status screen, press the Y button to view the error codes. Document these error codes.