2018-09-14 11:49:15: ERROR[Main]: ServerError: AsyncErr: ServerThread::run Lua: Runtime error from mod '*builtin*' in callback on_prejoinplayer(): /home/paul/minetest/bin/../builtin/game/auth.lua:134: attempt to index upvalue 'core_auth' (a nil value)
2018-09-14 11:49:15: ERROR[Main]: stack traceback:
2018-09-14 11:49:15: ERROR[Main]: 	/home/paul/minetest/bin/../builtin/game/auth.lua:134: in function </home/paul/minetest/bin/../builtin/game/auth.lua:130>
2018-09-14 11:49:15: ERROR[Main]: 	/home/paul/minetest/bin/../builtin/game/register.lua:419: in function </home/paul/minetest/bin/../builtin/game/register.lua:399>