Star Wars Battlefront 2 is still quite popular in 2019, and it's still plagued with network problems from time to time. Error Code 721 seems to be a particularly pervasive error, as it's been popping up since the game's release.
If you're looking for an Error Code 721 fix, we're sorry to say that no conclusive solution has yet been found, but you can try out a variety of Internet-related tweaks and fixes that may or may not solve the issue for you.
How to fix Star Wars Battlefront 2 Error Code 721?
According to what sources we could find, there's a variety of reasons you might be dealing with Error Code 721:
Your first step should always be to check if the game is down across the board. The best source of information for this sort of thing is undoubtedly the official Battlefront 2 Twitter, which is usually on top of relevant reports. In most cases, server outage is the reason you'll come across Error Code 721, but on the off chance you've stumbled into a local problem with your machine, perhaps one of the solutions below will help.
Release and Renew your IP Configuration
This is a simple tip that can help with a wide variety of Internet problems, and it's a good thing to keep in mind if you're unlucky enough to keep stumbling into issues.
- Hit Windows key + R
- Type 'cmd' into the newly-opened 'Run' window
- Hit CTRL + SHIFT + ENTER to open the Command Prompt with admin privileges
- Input 'ipconfig/release' into the black window and hit ENTER
- Input 'ipconfig/renew' and hit ENTER once the 'release' command is finished
That's all there is to it.
Change your default DNS
- Hit Windows key + R
- Type 'ncpa.cpl' into the newly-opened 'Run' window
- Find the network you're having trouble with in the newly-opened selection window and choose 'Properties' via the right-click menu
- Go to the 'Networking' tab and then click on the 'Settings' button
- Select 'Internet Protocol Version 4 (TCP/IPv4)' and click on the 'Properties' button
- Select the 'General' tab in the new window, and then click on the 'Use the following DNS server address' toggle'
- Replace the 'Preferred DNS server' values with 184.108.40.206
- Replace the 'Alternate DNS server' values with 220.127.116.11
Afterwards, you're going to want to do the same thing with 'Internet Protocol Version 6 (TCP/IPv6), but use 2001:4860:4860::8888 as your Preferred DNS server, and 2001:4860:4860::8844 as your Alternate DNS server. In some cases, this will solve your problem.
Disabling UPnP is a bit more complicated than any of the above. It's more difficult because you're going to have to access your particular router's settings interface, and it's potentially more problematic because turning it off could cause issues in games other than Battlefront 2.
You're going to want to open your web browser and type '192.168.0.1' or '192.168.1.1' in the address bar. Either could work, depending on your router's exact make and model. You can find an abundance of router-related information at portforward.com, which we recommend you consult before making any changes to your device's settings.
When the router UI is open, log into the device using the credentials provided by your ISP, and then navigate over to the 'NAT Forwarding' section of the interface. The exact naming may differ, but note that you're looking for some sort of a forwarding option with a section dedicated to UPnP. When the related option is located, just disable it, and see if the issue is resolved.
There's no guarantee any of these solutions will work, keep in mind. Error Code 721 seems to be particularly pervasive, and you may have some trouble in getting rid of it. That said, if nothing seems to work, perhaps restarting your PC and/or reinstalling the game could help.