diff --git a/parts/net.lua b/parts/net.lua
index b8b48801..a1e048f6 100644
--- a/parts/net.lua
+++ b/parts/net.lua
@@ -650,7 +650,7 @@ function NET.wsCallBack.room_enter(body)
         end
     else
         local p=body.data
-        if NETPLY.map[p.playerId] then _playerLeaveRoom(p.playerId) end
+        if NETPLY.exist(p.playerId) then _playerLeaveRoom(p.playerId) end
         NETPLY.add{
             uid=p.playerId,
             group=p.group,
diff --git a/parts/netPlayer.lua b/parts/netPlayer.lua
index d6b663ab..2973077e 100644
--- a/parts/netPlayer.lua
+++ b/parts/netPlayer.lua
@@ -138,6 +138,9 @@ function NETPLY.remove(uid)
         end
     end
 end
+function NETPLY.exist(uid)
+    return rawget(PLYmap,uid) and true or false
+end
 
 function NETPLY.setPlace(uid,place) PLYmap[uid].place=place end
 function NETPLY.setStat(uid,S)