Session server rejected incoming connection

[InFiNiX2231]

What happened?

a player couldn't join the server due to some IP address thing. Below is the error showing in the console

What did you expect?

No response

Steps to reproduce

No response

Plugin list

No response

Configuration file

No response

Server log

[23:30:19 ERROR]: [FastLogin] Session server rejected incoming connection for GameProfile Jyllieace (/). Possible reasons are1) Client IP address contacting Mojang and server during server join were different (Do you use a reverse proxy? -> Enable IP forwarding, or disable the feature in the config). 2) Player is offline, but tried to bypass the authentication3) Client uses an outdated username for connecting (Fix: Restart client)
[23:30:19 WARN]: [FastLogin] If you think this is an error, please verify that the incoming IP address / is not associated with a server hosting company.
[23:30:19 WARN]: [FastLogin] This indicates the use of reverse-proxy like HAProxy, TCPShield, BungeeCord, Velocity, etc. By default (configurable in the config) this plugin requests Mojang to verify the connecting IP to this server with the one used to log into Minecraft to prevent MITM attacks. In order to work this security feature, the actual client IP needs to be forwarding (keyword IP forwarding). This process will also be useful for other server features like IP banning, so that it doesn't ban the proxy IP.

Plugin version

1.12-SNAPSHOT-e15ea9c

Platform

Spigot

Relevance

• [X] I tried the latest build (build refers to development builds not necessary a release version)

• [X] I checked for existing tickets - If there are, please vote them with a thumbs reaction and not create new ones

[InFiNiX2231]

update enabled this useProxyAgnosticResolver: true. it worked?

[Chenyu550]

It may be caused by the player using IPv4 to connect to your server, but using IPv6 to connect to the mojang server.

[games647]

@Chenyu550

It may be caused by the player using IPv4 to connect to your server, but using IPv6 to connect to the mojang server.

Do have any reports of this happening. This sounds very strange, but possible if the Spigot server is only available using IPv4 and the session server is now available using both.

[Chenyu550]

@Chenyu550

It may be caused by the player using IPv4 to connect to your server, but using IPv6 to connect to the mojang server.

Do have any reports of this happening. This sounds very strange, but possible if the Spigot server is only available using IPv4 and the session server is now available using both.

Yes, my server only has IPv4 connection, but my PC has both. When I try to ping the mojang authserver on my PC, it returns an IPv6 address

[games647]

Well the vanilla client could disable IPv6, but it's very good idea you have.

[Asrieh]

Well the vanilla client could disable IPv6, but it's very good idea you have.

Hello, I have the same problem, how can I solve it?

[games647]

@Asrieh Read the log message. It stands exactly in it (reference change the config useProxyAgnosticResolver).

[daretmavi]

Can this work with paper server? One player can not login - with the same error as described, but useProxyAgnosticResolver: true didn't help.

Description in config says Please note that this setting has no effect when used outside of Spigot+ProtocolLib context. Paper is based on Spigot, co I hoped It could work.