R31A6-0:03 / R35A6-0-0:3 / S9041-TAD-W72T

Briefing:

You try to start a multiplayer session, host or join an online quest, and get the error "R31A6-0-0:3" or "S9041-TAD-W72T", or more frequently seen when attempting to join SOS quests, error "R35A6-0-0:3".

Likely Cause:

A network connectivity issue preventing the game from establishing the multiplayer session. The cause can vary and may involve regional data routing, a strict NAT type, or IPv6 routing.

Prerequisite:

Check if the servers are actually down.

Before troubleshooting your own network, check the official Monster Hunter status account at @MHStatusUpdates. If they are reporting a widespread outage or maintenance, the issue is on Capcom's end and no local fix will work. Wait for the servers to come back online.

General Fixes (try in order):

1. Disable IPv6.

Some networks may have IPv6 routing problems that do not affect IPv4. Disabling IPv6 forces the device to use IPv4 instead.

On PC:

On PlayStation and Xbox:

You will have to disable IPv6 through your router's admin page. Note that not all routers have such an option. If you wish to try, visit How to Disable IPv6 for Consoles. If you would like to try other steps first, continue reading.

Reminder: If disabling IPv6 did not resolve the issue, don't forget to re-enable it.

2. PC only: Change Virtual Private Network (VPN) status.

Some countries, like Egypt, encounter this error due to regional limitations. The game may treat connections differently based on their IP address or geographic origin. First, if you have a VPN enabled, try disabling it and see if that resolves the error. Otherwise:

If the error results because of how data is routed from your device to the game's servers, a VPN like Cloudflare's WARP changes that route, possibly resolving the issue. If you wish to try Cloudflare's WARP, you will need to download the application at 1.1.1.1.

After installing 1.1.1.1:

Note: If the error is related to how your connection is treated based on your geographic origin, then trying a VPN that makes it seem like you're connecting from a different country may bypass that. Cloudflare does not achieve that, but a more conventional VPN does. If you wish to test whether this is the case, I recommend trying Proton VPN, as it has unlimited data on its free plan.

3. Disable Crossplay.

This is especially relevant in certain countries with regional restrictions or limitations, but means losing the ability to play with different platform users. In Monster Hunter Wilds, this will also mean that you can only play with those who have their own Crossplay setting disabled.

To disable it:

If the issue is not resolved, or you need Crossplay on, continue reading.

4. PC only: Change network profile from public to private.

Low-confidence fix. A public network profile has stricter firewall rules than a private one. If such rules were the cause behind the error, a more lax private profile may work.

To do so:

If none of these fixes work:

The problem might be outside your control. It could be an issue with Capcom's multiplayer infrastructure or your ISP's routing. If the steps above did not resolve the issue, you can try reporting the problem to Capcom Support by filling out their technical inquiry contact form. Include your platform, region, ISP, error code, and the troubleshooting steps you already tried.