reopen the password dialog if user enters incorrect password

gui/qt/main_window.py

@@ -1982,9 +1982,16 @@ class ElectrumWindow(QMainWindow):
 
     def do_protect(self, func, args):
         if self.wallet.use_encryption:
+            while True:
                 password = self.password_dialog()
                 if not password:
                     return
+                try:
+                    self.wallet.check_password(password)
+                    break
+                except Exception as e:
+                    QMessageBox.warning(self, _('Error'), str(e), _('OK'))
+                    continue
         else:
             password = None