1.21.11 build 103 denying all logins with Server full!

[awhitcroft]

Expected behavior

Expecting to be able to login to the server as normal

Observed/Actual behavior

Since upgrading to 1.21.11 build 103 all attempts to connect to the server are denied "Server full".

Steps/models to reproduce

Start build 103 and attempt to join world.

Plugin and Datapack List

/plugins
[22:27:33 INFO]: ℹ Server Plugins (6):
[22:27:33 INFO]: Bukkit Plugins:
[22:27:33 INFO]: - Chunky, Essentials, floodgate, Geyser-Spigot, LuckPerms, Vault
/datapack list
[22:28:22 INFO]: There are 3 data pack(s) enabled: [vanilla (built-in)], [file/bukkit (world)], [paper (built-in)]
[22:28:22 INFO]: There are no more data packs available

Paper version

/version
[22:29:19 INFO]: Checking version, please wait...
[22:29:19 INFO]: This server is running Paper version 1.21.11-103-main@e5718dc (2026-02-04T19:08:57Z) (Implementing API version 1.21.11-R0.1-SNAPSHOT)
You are running the latest version
Previous version: 1.21.11-100-4873e3f (MC: 1.21.11)

Other

No response

[awhitcroft]

As expected downgrading just paper to 1.21.11-100 (the previously used version) restores the ability to login to the server normally.

[Doc94]

Looks like its a issue with Essentials where if you configure a full server message (isCustomServerFullMessage) its set to the deny in all cases causing the issue.
ref: https://github.com/EssentialsX/Essentials/blob/77756620cf83a9fbc81170eda2340e7e980f8abf/providers/PaperProvider/src/main/java/net/essentialsx/PaperAdventureSmuggler.java#L21

[awhitcroft]

Looks like its a issue with Essentials where if you configure a full server message (isCustomServerFullMessage) its set to the deny in all cases causing the issue. ref: https://github.com/EssentialsX/Essentials/blob/77756620cf83a9fbc81170eda2340e7e980f8abf/providers/PaperProvider/src/main/java/net/essentialsx/PaperAdventureSmuggler.java#L21

Confirmed that setting the EssentialsX configuration use-custom-server-full-message: false avoids the issue.

Will report against EssentialsX. Thank you for looking at this.

[awhitcroft]

For completeness, this is reported on EssentialsX as EssentialsX/Essentials#6424.

[DereC4]

Holy cow this is happening to me and still is, I'm so glad someone reported.