Problem: Call of Duty World War 2 (WWII) prompt error “service is not available at this time” with error code 4220 and unable to connect to online multiplayer mode.
Content Summary
Solution 1: Power Cycling Console
Solution 2: Login to WWII Nazi Zombies before connect to normal multiplayer
Solution 3: Check Internet connection settings from console
Solution 4: Set the right NAT type
Reference
Solution 1: Power Cycling Console
Completely shut down your console, router, modem and plug out main power supply for around 5 minutes in order to erase any bad configurations and refresh their state.
Error Code 4220 also seems to be quite common as well.
— Black Ops 4 (@BlackOps4INTEL) November 3, 2017
Solution 2: Login to WWII Nazi Zombies before connect to normal multiplayer
Step 1: Launch Call of Duty WWII on your console, connecting to Xbox Live, then click the option Nazi Zombies.
Step 2: Click on Multiplayer to navigate back to the main menu.
Error Code 4220 from r/WWII
Solution 3: Check Internet connection settings from console
Step 1: Open console settings > Network > Test Internet Connection.
Step 2: Now console will start to check the internet connection details and confirm the connection is established.
Step 3: Now open Call of Duty WWII again and try connecting to Xbox Live.
Solution 4: Set the right NAT type
For Xbox, it is recommended that NAT type set to Open. Go to Settings > All Settings > Network > Test NAT type and make sure it is set to Open.
For PS4 the NAT type should be Type 1. Go to Settings > Network > Connection Status > Set NAT type to Type 1.
Reference
WORLD WAR II SUPPORT: ERROR CODE: 4220!!!!
WORLD WAR II PS4: Error Code 4220
Steam Community: Call of Duty: WWII – Multiplayer: code error 4220