Error Code 400 is a common issue many Roblox players face when opening the game client. If you are affected by this issue, you probably can’t join any game or host one since you can’t reach the main Roblox lobby.
This error happens in most cases due to the servers going through problems or being under maintenance. Besides that, it could also happen when your Roblox game client is outdated.
Here is a list of all the methods that you need to do to fix the following error:
1. Check for a server issue
Most of the time, a server issue or scheduled maintenance is the leading cause of the Roblox error code 400. You first need to check the server’s status to see if the servers are down.
Most likely, the central server for finding matches is down, and developers are working on it to fix it.
You can use sites like Downdetector to check the server status and see if other people have reported problems with the server. This site will show how many reports have been made in the last 24 hours.
This will let you know if the error code 400 in Roblox is happening to others or just to you.
You can also go to the Roblox Twitter page to see if the developers have said anything about servers being down. This page is dedicated to updating users about the current server status.
If you found recent posts about server problems happening, read the comments to find out what other players have said about it.
If you can confirm that there is a problem with the server and other people are also experiencing the 400 error code, you can only wait until the developers fix it.
2. Perform a Winsock Reset
Roblox error code 400 might be caused by network inconsistencies. A Winsock reset should be enough to fix these issues since it will clear temporary network data.
A Winsock reset is a command that will also reset some important settings to the ‘safe’ defaults, which may fix the problem in your case. All you have to do is to use the Command Prompt with administrator privileges.
Note: This command won’t affect your computer files or your access to the internet.
Here are the steps you need to follow:
- Press the Windows + R button to open a Run dialog box, then type ‘cmd‘ inside the search bar and press CTRL + Shift + Enter to open the Command Prompt with administrator privileges.
- You must click Yes to confirm that you give Command Prompt admin privileges.
- Once you are inside the Command Prompt, you need to type the following commands inside it, then press Enter after each other:
ipconfig /flushdns netsh winsock reset
- When you have deployed both commands succesfully, close the Command Prompt by typing exit or clicking the X button.
- Now you need to launch Roblox to see if the problem is fixed.
If the error code 400 still appears even after doing this, try the next fix down below.
3. Run Windows Diagnostics Troubleshooter
Another thing you can try is to run the Windows Network Troubleshooter. This process will scan your network to see if it finds any problems. If problems are found, the troubleshooter will attempt to fix the network issues automatically.
To run the Windows Diagnostics Troubleshooter, you must go to the Windows Settings and find the Other Troubleshooters. The Network Adapter should be there – run it to start the troubleshooter.
Here’s how you can do it:
- You need to start by opening the Windows Settings. Open the taskbar and search Settings, then press Enter to open it.
- Once you are inside the Settings, select the System tab and click on the Troubleshoot tab.
- Now click on the Other troubleshooters tab to see the list of all the troubleshooters.
- Scroll down until you find the Network Adapters troubleshooter, then click on Run.
- If the troubleshooter finds any problems, let it fix them.
- When the troubleshooting process is complete, close the window and launch Roblox to see if the error code 400 is now fixed.
If you’ve tried everything and the error still appears when playing Roblox, go to the next and last method available.
4. Change DNS to CloudFlare or Google
The last thing you should try is to change the DNS to Cloudflare equivalents. This should fix your problem because you are moving your DNS range to a more stable domain name address.
This can be done from the Control Panel window of your computer. This fix can be replicated on every recent Windows version.
Here is a guide that will show you how to do this:
- The first thing you need to do is to open the Network Connections window. Press the Windows key + R and type ‘ncpa.cpl‘, then press Enter.
- Now you need to locate the internet connection that you are currently using. When you see it, right-click on it and click on Properties.
- When the Properties appear on your screen, select the Networking tab and look for Internet Protocol Version 4 (TCP/IPv4). Select it and click on Properties.
- Once you’ve done that, click on Use the following DNS server addresses and type the following numbers inside them:
22.214.171.124 for Preferred DNS server 126.96.36.199 for Alternate DNS server
Note: These numbers are the equivalents for the CloudFlare DNS.
- When you are done with that, click OK, and the DNS should be changed successfully.
- Now all that’s left to do is to launch Roblox to see if the error code 400 still occurs.