Who can tell me what's wrong?

I have three dst servers,but the second time I can't connect one to master(the other can connected).

and here are ERROR information

LUA ERROR stack traceback:
    scripts/tuning_override.lua:40 in (upvalue) SetSpawnMode (Lua) <38-42>
    scripts/tuning_override.lua:47 in (field) ? (Lua) <46-48>
    scripts/gamelogic.lua:398 in (upvalue) PopulateWorld (Lua) <251-454>
    scripts/gamelogic.lua:671 in (upvalue) DoInitGame (Lua) <554-757>
    scripts/gamelogic.lua:789 in (upvalue) cb (Lua) <784-790>
    scripts/saveindex.lua:281 in () ? (Lua) <263-282>
    =[C]:-1 in (method) GetPersistentString (C) <-1--1>
    scripts/saveindex.lua:263 in (method) GetSaveDataFile (Lua) <262-283>
    scripts/saveindex.lua:289 in (method) GetSaveData (Lua) <285-293>
    scripts/gamelogic.lua:791 in (upvalue) DoLoadWorld (Lua) <783-792>
    scripts/gamelogic.lua:832 in (upvalue) LoadSlot (Lua) <827-838>
    scripts/gamelogic.lua:887 in (upvalue) DoResetAction (Lua) <842-923>