diff --git a/nemubot/bot.py b/nemubot/bot.py
index d83f22e..d5510a7 100644
--- a/nemubot/bot.py
+++ b/nemubot/bot.py
@@ -138,17 +138,17 @@ class Bot(threading.Thread):
                 fnd_smth = False
                 # Looking for invalid server
                 for r in _rlist:
-                    if not hasattr(r, "fileno") or not isinstance(r.fileno(), int) or r.fileno() == -1:
+                    if not hasattr(r, "fileno") or not isinstance(r.fileno(), int) or r.fileno() < 0:
                         _rlist.remove(r)
                         logger.error("Found invalid object in _rlist: " + r)
                         fnd_smth = True
                 for w in _wlist:
-                    if not hasattr(w, "fileno") or not isinstance(w.fileno(), int) or w.fileno() == -1:
+                    if not hasattr(w, "fileno") or not isinstance(w.fileno(), int) or w.fileno() < 0:
                         _wlist.remove(w)
                         logger.error("Found invalid object in _wlist: " + w)
                         fnd_smth = True
                 for x in _xlist:
-                    if not hasattr(x, "fileno") or not isinstance(x.fileno(), int) or x.fileno() == -1:
+                    if not hasattr(x, "fileno") or not isinstance(x.fileno(), int) or x.fileno() < 0:
                         _xlist.remove(x)
                         logger.error("Found invalid object in _xlist: " + x)
                         fnd_smth = True