Currently, SophisticatedCore appears to prevent players from connecting to non-NeoForge servers (such as vanilla or proxy lobbies like BungeeCord/Velocity).

This breaks setups where:
A proxy network (BungeeCord, Velocity, etc.) has a vanilla lobby/login server.
Players must connect to the lobby first, then transfer to a modded server.
Because SophisticatedCore forces a NeoForge server check, players get disconnected with:
"You are trying to connect to a server that is not running NeoForge..."

use https://modrinth.com/mod/be-quiet-negotiator