internal exception: java.net.socketexception connection reset

[Underscore-163]

Describe the bug
When I try to connect to my server, I get the error internal exception: java.net.socketexception connection reset on my minecraft screen. I do get the blue text/icon to indicate modflared is doing its thing. Modflared is the only mod installed as this is a test to make sure modflared will work with my setup.

Which version of the mod/game are you using?
CurseForge Forge 1.20.1

To Reproduce
Steps to reproduce the behavior:

1. Set up cloudflare domain and tunnels
2. Add DNS record
3. Start client
4. Connect to server
5. error.

Expected behavior
It should (as I understand it) just let me connect to the server with no issues. I have seen a couple of tutorials that show it just working with the setup I have.

Screenshots

[HttpRafa]

Could you attach the game logs to the issue?

[Underscore-163]

the relevant part of the logs seem to be this (it repeats every time I try to connect):

[10:58:51] [Render thread/INFO]: Connecting to modflared.my-domain.net, 25565
[10:58:51] [Server Connector #4/INFO]: Starting tunnel to modflared.my-domain.net
[10:58:51] [pool-7-thread-5/INFO]: [cloudflared-windows-amd64.exe access tcp --hostname modflared.my-domain.net --url 127.0.0.1:34528]
[10:58:51] [pool-7-thread-5/INFO]: 2026-06-30T09:58:51Z INF Start Websocket listener host=127.0.0.1:34528
[10:58:52] [pool-7-thread-5/INFO]: 2026-06-30T09:58:52Z ERR failed to connect to origin error="websocket: bad handshake" originURL=https://modflared.my-domain.net
[10:58:52] [Netty Client IO #7/INFO]: Stopping tunnel to /127.0.0.1:34528

hope this helps!

Edit: some more information in case it helps:

• the server is hosted through crafty controller 4, which itself runs in a VM hosted by incus (but it is accessible through the local network, so that isn’t the issue).
• the server is running on port 25555, but that is also where I've told cloudflare to direct to, so I don't think that's the issue either.