diff --git a/qweechat/connection.py b/qweechat/connection.py
index d867d2a..7f1884d 100644
--- a/qweechat/connection.py
+++ b/qweechat/connection.py
@@ -45,6 +45,10 @@ class ConnectionDialog(QtWidgets.QDialog):
         line_edit = QtWidgets.QLineEdit()
         line_edit.setFixedWidth(200)
         value = self.values.get('hostname', '')
+        if value in ['None', None]:
+            value = '0'
+        elif type(value) == int:
+            value = str(value)
         line_edit.insert(value)
         grid.addWidget(line_edit, 0, 1)
         self.fields['hostname'] = line_edit
@@ -56,6 +60,10 @@ class ConnectionDialog(QtWidgets.QDialog):
         line_edit = QtWidgets.QLineEdit()
         line_edit.setFixedWidth(200)
         value = self.values.get('port', '')
+        if value in ['None', None]:
+            value = '0'
+        elif type(value) == int:
+            value = str(value)
         line_edit.insert(value)
         grid.addWidget(line_edit, 1, 1)
         self.fields['port'] = line_edit
@@ -73,6 +81,10 @@ class ConnectionDialog(QtWidgets.QDialog):
         line_edit.setFixedWidth(200)
         line_edit.setEchoMode(QtWidgets.QLineEdit.Password)
         value = self.values.get('password', '')
+        if value in ['None', None]:
+            value = '0'
+        elif type(value) == int:
+            value = str(value)
         line_edit.insert(value)
         grid.addWidget(line_edit, 2, 1)
         self.fields['password'] = line_edit
diff --git a/qweechat/input.py b/qweechat/input.py
index 8ffcd29..98b05bd 100644
--- a/qweechat/input.py
+++ b/qweechat/input.py
@@ -23,7 +23,7 @@
 """Input line for chat and debug window."""
 
 from  qtpy import QtCore, QtWidgets
-from  qtpy.QtCore import pyqtSignal as Signal
+from  qtpy.QtCore import Signal
 
 class InputLineEdit(QtWidgets.QLineEdit):
     """Input line."""
diff --git a/qweechat/network.py b/qweechat/network.py
index 149837d..0127a98 100644
--- a/qweechat/network.py
+++ b/qweechat/network.py
@@ -27,7 +27,8 @@ import secrets
 import struct
 
 from  qtpy import QtCore, QtNetwork
-from  qtoy.QtCore import pyqtSignal as Signal
+# from PyQt5.QtCore import pyqtSignal as Signal
+from  qtpy.QtCore import Signal
 
 from qweechat import config
 from qweechat.debug import DebugDialog
@@ -231,7 +232,19 @@ class Network(QtCore.QObject):
 
     def is_connected(self):
         """Return True if the socket is connected, False otherwise."""
-        return self._socket.state() == QtNetwork.QAbstractSocket.ConnectedState
+        return is_state(self, at='ConnectedState')
+
+    def is_state(self, at='ConnectedState'):
+        """Return True if the socket is connected, False otherwise."""
+        if hasattr(QtNetwork.QAbstractSocket, 'ConnectedState'):
+            if self._socket.state() == getattr(QtNetwork.QAbstractSocket, at):
+                return True
+            return False
+        if hasattr(QtNetwork.QAbstractSocket, 'SocketState'):
+            if self._socket.state() == getattr(QtNetwork.QAbstractSocket.SocketState, at):
+                return True
+            return False
+        return False
 
     def is_ssl(self):
         """Return True if SSL is used, False otherwise."""
@@ -251,9 +264,10 @@ class Network(QtCore.QObject):
             self._lines = int(lines)
         except ValueError:
             self._lines = config.CONFIG_DEFAULT_RELAY_LINES
-        if self._socket.state() == QtNetwork.QAbstractSocket.ConnectedState:
+        # AttributeError: type object 'QAbstractSocket' has no attribute 'ConnectedState'
+        if self.is_connected():
             return
-        if self._socket.state() != QtNetwork.QAbstractSocket.UnconnectedState:
+        if not self.is_state('UnconnectedState'):
             self._socket.abort()
         if self._ssl:
             self._socket.ignoreSslErrors()
@@ -264,10 +278,10 @@ class Network(QtCore.QObject):
 
     def disconnect_weechat(self):
         """Disconnect from WeeChat."""
-        if self._socket.state() == QtNetwork.QAbstractSocket.UnconnectedState:
+        if self.is_state('UnconnectedState'):
             self.set_status(STATUS_DISCONNECTED)
             return
-        if self._socket.state() == QtNetwork.QAbstractSocket.ConnectedState:
+        if self.is_state('ConnectedState'):
             self.send_to_weechat('quit\n')
             self._socket.waitForBytesWritten(1000)
         else: