MHW Error Code 400-MW1 (FIXED)



You might have run into MHW error code 400-MW1 when playing Monster Hunter World. This error code can be especially frustrating because it does not allow you to participate in event quests or see login rewards. In some cases, you might be able to go online with no issues and join parties or sessions. However, despite your persistent efforts, the event quests disappear without any signs of returning. 

Key Takeaways

  • Monster Hunter World error code 400-MW1 shows up when you try to access event quests. It can prevent you from seeing the event quest list and claiming login rewards.
  • The reason this error code shows up is likely because of your global IP address. Something is stopping your IP from communicating with the MHW servers.

  • Follow these methods to fix error code 400-MW1:
    • Temporarily use a Hotspot or VPN connection to access the event quests, then connect back to your internet. Note that the event quest will disappear once again when you refresh.
    • Open the network ports on your router that Monster Hunter World requires.
    • Get an open NAT connection. Additionally, check your internet speed and confirm it is not under 8 MBPS.
    • Ultimately, if nothing is working for you, contact the official Capcom customer support.

What Causes Error Code 400-MW1?

Capcom has not officially revealed what exactly causes error code 400-MW1. But if we take an educated guess, it likely happens because your global IP address cannot communicate with the event quest servers. This could be due to various reasons, like a potential soft ban, NAT issues, closed ports, or even a slow internet connection. You can also encounter error code 400-MW1 if the Monster Hunter World servers are down.

In the case of NAT issues, closed ports, or offline servers, you will likely be unable to enter any parties or sessions. On the other hand, a global IP address issue or slow internet might allow you to join your friends but not event quests. Do note that the causes behind MHW error code 400-MW1 are not limited to these things. These are the most common culprits and may not necessarily apply to your specific situation. 

The error itself shows the same message every time and presents itself in a pop-up box like this:

mhw error code 400-MW1 fixed
MHW error code 400-MW1 (Image by Exputer)

How To Fix Monster Hunter World Error Code 400-MW1?

We know that the main cause of error code 400-MW1 revolves around your global IP address. While that is easy to understand, how you approach fixing this IP address issue can seem slightly complicated. The main thing you will need to do is somehow change your IP address. You can achieve this by using a VPN connection, contacting your internet service provider, or using other methods. Here are some methods to help you resolve this issue. 

Temporarily Use A Mobile Hotspot Or VPN Connection

First, you need to confirm if MHW error code 400-MW1 is occurring because of your internet connection. For console users, the easiest way to verify this is to use a Mobile Hotspot temporarily. Disconnect from your internet and connect to your mobile hotspot, then launch MHW to see if the error is resolved. PC users can similarly use a VPN connection instead; any free VPN service will work. Both of these methods will change your global IP address.

If you can access event quests through these methods, the issue is on your internet’s end. This can either be your global IP address or a restricted NAT type. A quick workaround you can do here is to remain at the event quest menu with your VPN connection or Hotspot running. Now, disconnect them and connect back to your internet connection.

This will allow you to keep the event quests and participate in them. Unfortunately, this is only a workaround and does not solve the root problem. When you refresh, the error code will inevitably pop up again, and you will have to repeat the workaround.

While most players might be content with this workaround, you might search for a more definitive solution that directly attacks the underlying problems. If so, try out more of the methods mentioned below.

Open Ports In Your Router

Closed ports on your router are one of the most common culprits behind network or server-related errors. In this case, if the ports that MHW requires are closed on your router, you will likely encounter error code 400-MW1. To describe a port in its simplest terms, it serves as a distinct numerical identifier used to recognize the endpoint of a network. All of your network traffic is directed by these ports to any specific network endpoint. These endpoints can represent a wide range of things, from physical servers to online services or even IP addresses.

The network endpoint we need to reach for MHW is its server. If the MHW ports are closed, the network traffic cannot travel to its servers, effectively denying you access to the network features. You can open ports directly from your network router to fix this. Note that it is essential to exercise caution and only open the ports that are genuinely required. Opening ports you do not need can potentially expose you to various malware and hackers.

These are all the ports you need to ensure smooth traffic flow to Monster Hunter World. Please only open the ports that apply to your platform:

PlayStation 4:

  • TCP: 1935, 3478, 3479, and 3480
  • UDP: 3074, 3478, and 3479

Xbox One:

  • TCP: 3074
  • UDP: 88, 500, 3074, 3544, and 4500


  • TCP: 27015-27030 and 27036-27037
  • UDP: 4380, 27000-27031, and 27036

How To Open Ports

  1. Look at the back of your network router and note down its IP address and login information.
  2. Enter the IP address in any browser and log in. Once in, find the port forwarding setting. Most routers call this setting virtual serversNAT, or port triggering.
  3. When you enter the setting, add the port range you want to open. Some routers might ask for a name. If so, enter Monster Hunter World.
  4. Once you have added all the necessary ports, save the settings and reboot your router to apply the changes.
Minecraft legends login error fix
Opening Ports (Credits to Exputer)

Get An Open NAT Connection

Similarly to ports, the NAT type helps in network communication. While ports can direct network traffic, your NAT type pushes the traffic forward to reach the endpoint. NAT type is especially apparent when you try to connect to other players online. There are a total of 3 NAT types; Open NAT, Moderate NAT, and Strict NAT. They are also known as Type 1, Type 2, and Type 3.

If your NAT type is strict, you likely cannot communicate with other players properly. You may experience frequent server disconnections and encounter several errors, such as MHW error code 400-MW1. Moderate NAT functions adequately, while an open NAT is a best-case scenario. However, it is crucial to always avoid a strict NAT type as it makes gaming online nearly impossible.

Before attempting to change your NAT type, it is essential to determine the specific type of NAT connection you currently have. You do not need to change anything if your NAT type is moderate or open.

Check NAT Type On PlayStation 4

  1. Go to your PlayStation 4’s system settings and enter the network section.
  2. Inside the network section, select Test Internet Connection.
  3. The PlayStation 4 will perform a full test of your internet, which includes your NAT Type. If it is type 3, your NAT is strict.
get open nat type on ps4
NAT Type on PlayStation 4 (Image credits to Exputer)

Check NAT Type On Xbox One

  1. Open your Xbox settings and make sure you are in the general settings section.
  2. Here, enter Network Settings.
  3. On the right, click Test NAT type to know the type of your NAT connection.
open nat type on xbox one
Nat type on Xbox One (Image copyright: Exputer)

Check NAT Type On A PC

  1. Click on the Windows icon on your desktop to open the start menu. Here, click on the gear icon to enter Windows settings.
  2. Now click on Gaming and then Xbox Networking.
  3. The test will be performed automatically and might take a few minutes.
checking NAT type on PC
NAT type on a PC (Image provided by Exputer)

How To Open NAT Type

You can use countless methods to open your NAT type, but the fastest and easiest approach is to enable UPnP in your router. Here is how to do it:

  1. Follow the first step of the How To Open Ports section and log into your router.
  2. Now, locate the UPnP setting. In most routers, it is typically found under network settings or the advanced section.
  3. Once the setting is found, enable UPnP. You will need to reboot your router so it can take effect. This will open your NAT Type.
open nat type for mhw errors
Enabling UPnP in router settings (Image: Exputer)

If, for some reason, your NAT Type stays as strict, it is likely from your internet service provider’s end. In this case, you must contact your ISP and discuss this issue with them.

Check Your Internet Speed

If your internet is not up to par with what is required to run Monster Hunter World, you will likely encounter error code 400-MW1. You should ensure that your download and upload speed is at least higher than 8 MBPS. If it is not, your latency will be affected, which means the data packets will not be able to travel fast enough to communicate. To check your internet speed, visit and click the big Go button in the middle of the page.

internet speed test for mhw error code
Internet Bandwidth test (Image: Exputer)

If your internet speed is consistently above 8 MBPS, a slow internet connection is not the reason why you are experiencing error code 400-MW1. To increase your internet speed, you will likely have to contact your internet service provider and upgrade your package.

In case you are using WiFi, you should switch to an Ethernet cable immediately. Ethernet cables are cost-effective and work much better than a WiFi connection. This is because they connect you directly to your network router, allowing optimal and consistent network speeds.

Contact Capcom Customer Support

If nothing has worked for you so far, you have no choice but to contact the official Capcom customer support for Monster Hunter World. Something could be wrong with your game that only the support team can fix. They will likely ask you for an MSINFO and DxDiag file, so they can accurately pinpoint the cause behind your MHW error code 400-MW1. Rest assured, as the support team will provide the necessary instructions to create these files.

To contact the support team, go to this website and follow the instructions that apply to your region. Do make sure to confirm the status of MHW’s servers, as offline servers can also cause error code 400-MW1.

Did You Resolve The Error Code?

Monster Hunter World is a relatively old game that has seen a sequel called Monster Hunter Rise. Despite this, some incredibly loyal players still consistently play MHW. As of the writing of this article, MHW is still getting around ~12K daily players on Steam. This aspect makes MHW particularly worthwhile to invest time in, especially considering that matchmaking works swiftly even to this day. With error code 400-MW1 fixed, you can tackle those event quests once again and claim your daily rewards. 


What does error code 400-MW1 do?

This error code can prevent you from accessing your daily rewards and the event quests. You might still be able to join parties and sessions.

How do I get an Open NAT Type?

The fastest way to change a strict NAT type is to access your router settings and enable UPnP.

Will opening ports affect the performance of my internet connection?

No, you will not notice any negative effects on your internet after opening ports. Make sure to only open the ports you need, as opening unnecessary ports can be dangerous.

Our Other Helpful Guides on Monster Hunter World:

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