I'm trying to direct connect with a friend, like we have done during early access. We are now getting a NATPunch (66) error when we try to join each other.

Tried firewall rules, disabling AV, VPNs, public lobby instead of direct connect. Any suggestions?

Hi, im gonna leave this comment here because ive been having trouble with the same exact error with a friend we get the nat punch 66 error i hope someone has a solution

Thats actually not the issue here me and my friend have the same version and both have the game on GOG but direct connect still shows NATpunch 66

Im having the same issue but my friends are on steam, they both are able to direct connect to each other but when I try to connect to any of them it gives the natpunch error, they also get it if Im the one hosting. I've tried many things from the internet but so far no luck.

did you find any solution?

the issue is with gog direct connect servers is really broken is practically imposible to play online with different plataforms at this time

Where did you put the firewall rules in? You should disable the Windows firewall, and open up the ports in your router firewall, and not in Windows firewall. This worked for me. It is a bit buggy though, the friend on steam who is hosting the game has my name. Every time it is his turn it says its my turn lol.

These are the ports:

TCP: 27015, 27036
UDP: 27015, 27031-27036

I'm having the same problem Natpunch 66
We tried everything from direct connect, to lobby, nothing works.

Hello!

I ran into the same issue in Divinity Original Sin 2 DE. The game was running smoothly yesterday, but when I attempted to connect to my friend's game this evening using the Direct Connect code, I encountered the following error message: "Connecting to NATpunch server failed. Connecting via online wasn't successful either."

I managed to resolve the problem by performing a verification and repair process for the game in GOG. To do this, follow these steps:

1. Select the game in your GOG library.
2. Click on the settings menu at the top (located next to the play button).
3. Choose "Manage installation."
4. Then, select "Verify / Repair."

Try this, maybe it will also work for BG3.

If you purchased the game on Steam, you can try repairing it through the Steam platform.

Now we are in 2024 and NATpunch (66) still persists. Why can't GoG just fix their shit?

It happened to me as well.
I purchased BG3 on GOG and I can't play with all my friends on Steam.
Natpunch 66. We have tried everything for hours.

I requested a refund.

Today I contacted my ISP.
I forwarded the ports yesterday as recommended by Larian but there was still some block.
A tech solved it. So I can play with friends who purchased BG3 on Steam. I will no longer ask for a refund.

Good ending.

Which tech solved it? Larian? GOG? ISP?

it will be an isp issue and the tech made him a small tunnel

I got the game on Steam, but I still encountered the issue and figured it would help if I post here because this issue is much more common with GOG than it is with Steam.

Steam users usually won't encounter this issue because Steam offers TURN relays (Steam Datagram Relay). BG3 is a peer-to-peer game and doesn't support IPv6. Therefore, for GOG connectivity to work, either the host or all non-Steam clients must have a dedicated (also called public) IPv4 address. Connectivity will not work if both sides are behind a CGNAT or Dual Stack Lite.

If you got a dedicated IPv4 address, you will need the following ports: UDP 23243 - 23262.
You don't need to forward them if your router is UPnP capable (BG3 will do it for you), but you will have to unblock them in your firewall if you use a firewall.

Alternatives to obtaining a dedicated IPv4 address are either getting the game on Steam or using a VPN server with port forwarding (same ports) or using a virtual LAN tunneling solution such as ZeroTier (in that case, use the ZeroTier LAN IP of the host instead of a Direct Connect ID as the ID to enter).