Why the Open to LAN Button Is Greyed Out on Servers

This Is Intentional

The disabled "Open to LAN" button is not a bug. It is the mod restoring the pre-1.19.1 menu layout, where that button occupied the slot and was inactive while you were connected to a remote server. Opening a world to LAN only makes sense in singleplayer, so the button is shown but cannot be pressed on a multiplayer server.

What You Can and Cannot Do

• You cannot click the greyed out button while on a server. This is expected behavior.
• You cannot use it to host the server world to your LAN. That is not what the button does in this context.
• If you want to actually open a world to LAN, leave the server and load a singleplayer world instead.

If the Button Behaves Differently

If the button appears active and clickable while you are on a server, another mod is likely modifying the same screen. Disable other menu-altering mods one at a time to find the conflict. If the button is missing entirely rather than greyed out, the mod may not be applying its replacement, which usually means a version mismatch between the mod and your game.