Error executing command on behalf of the player

[mrdeniska1234]

I get an error when trying to call a lobby command on a banjcord server on behalf of a player. The version is 2.8.2.
Core bungee - flamecord 1.21.4
spigot - 1.21.4 purpur

[14:06:27 INFO] [CommandSyncServer]: [127.0.0.1:56709]-[MA1] Received input player@#@single@#@lobby@#@MrDeniska1234
[14:06:27 ERROR]: java.lang.UnsupportedOperationException: Cannot spoof chat on this client version!
[14:06:27 ERROR]: 	at net.md_5.bungee.UserConnection.chat(UserConnection.java:560)
[14:06:27 ERROR]: 	at sawfowl.commandsyncserver.bungee.ClientHandler.run(ClientHandler.java:87)