diff --git a/.gitignore b/.gitignore
index d02036f96a65ad892d7efcb07f1b270465df1731..fac4925fe73c3e5b7c043cdfd2cd4cc7b6312feb 100644
--- a/.gitignore
+++ b/.gitignore
@@ -114,3 +114,5 @@ venv.bak/
 .vscode/settings.json
 
 logs/
+
+private_testing/
diff --git a/README.md b/README.md
index 8748f4513e716cd9e2a119bfdfc71d9aaf1c6daa..f972812e884890e9a366902b49df9e9b3d6fbd34 100644
--- a/README.md
+++ b/README.md
@@ -79,6 +79,9 @@ To obtain credentials for MQTT-Broker of WZL-MQ-MS contact [Mark Sanders](mailto
 For more detailed explanation and full API documentation, view [https://iot.wzl-mq.rwth-aachen.de/documentation/libs/mqtt/](https://iot.wzl-mq.rwth-aachen.de/documentation/libs/mqtt/)
 
 ## Changelog
+2.4.1
+- made the error message of code 1 more precise
+
 2.4.0
 - added vhost parameter to connect function of client
 - changed default logging behaviour
diff --git a/setup.py b/setup.py
index 7ce55fa730211a04711ff3e4894359da551fcf55..cc01c2f5571b2eb75171e06bfd244c332f71230d 100644
--- a/setup.py
+++ b/setup.py
@@ -1,7 +1,7 @@
 from setuptools import setup, find_packages
 
 setup(name='wzl-mqtt',
-      version='2.4.0',
+      version='2.4.1',
       url='',
       author='Benjamin Montavon, Matthias Bodenbenner',
       author_email='m.bodenbenner@wzl.rwth-aachen.de',
diff --git a/src/mqtt/client.py b/src/mqtt/client.py
index a17815c1586a3dd17d4e8b95e563d103b2173e7f..ba065ca1ec84790a053a85fad18069b1b29238a6 100644
--- a/src/mqtt/client.py
+++ b/src/mqtt/client.py
@@ -144,10 +144,12 @@ class MQTTClient:
     def _on_disconnect(self, client, userdata, rc):
         if rc == 1:
             self._logger.error(
-                "MQTT Client {} disconnected with code {} ({}). \n \t There are two possible reasons: \n"
-                "\t\t 1. You may tried to use Publisher-Credentials for receiving messages or vise versa.\n"
-                "\t\t 2. You tried to publish to or subscribe a topic which you are not allowed to do. \n"
-                "Please contact Mark Sanders or Matthias Bodenbenner, to check if your login credentials are correct!".format(
+                "MQTT Client {} disconnected with code {} ({}). \n \t There are various possible reasons for that: \n"
+                "\t\t 1. You used port 8883 but did not set the 'ssl' flag (or used port 1883 and set the 'ssl' flag).\n"
+                "\t\t 2. You may tried to use Publisher-Credentials for receiving messages or vise versa.\n"
+                "\t\t 3. You tried to publish to or subscribe a topic which you are not allowed to do. \n"
+                "\t\t 4. Something else, which has not been experienced by the developers of this library. Sorry!\n"
+                "If you don't find a solution, please contact Mark Sanders or Matthias Bodenbenner to check if your login credentials are correct!".format(
                     self.name, rc, mqtt.error_string(rc)))
         else:
             self._logger.info(