When a server starts up, at one point it'll say:

[Server thread/INFO]: Done (<something>s)! For help, type "help" or "?"

but typing "?" will result in

[Server thread/INFO]: Unknown command at position 0: <--[HERE]

Fixing this can be done in 2 simple ways:

1. Change the message to not say or "?".
2. Re-add ? as an alias of help.