Please read the following first:
It is almost impossible to read your posts, therefore its even harder to analyze what’s wrong in your setting.
I see, you have got several errors:
09:38:06.415 [ERROR] [openhab.io.transport.mqtt.MqttService] - Error starting broker connection
org.eclipse.paho.client.mqttv3.MqttException: MqttException#
...
Caused by: java.net.SocketException: Connection reset
So for me it seems that the MQTT binding cannot connect to the broker. Please check if all settings are correct
After that you get many parsing errors:
09:38:05.671 [ERROR] [del.item.internal.GenericItemProvider] - Binding configuration of type ‘mqtt’ of item ‘Bathroom_Temperature’ could not be parsed correctly.
org.eclipse.smarthome.model.item.BindingConfigParseException: Configuration ‘flatcntr:/TempCNTR/test/Temperature:string:default’ is not a valid inbound configuration: Invalid type.
I guess that the STRING here is wrong. From my experience it is always either a state or a command.
09:56:07.151 [WARN ] [.ui.internal.items.ItemUIRegistryImpl] - Exception while formatting undefined value [sourcePattern=%.1F %ºC, targetPattern=%1$s %ºC, {}]
java.util.UnknownFormatConversionException: Conversion = ‘º’
You might want to use a lower case “f” here. See also Formatter (Java Platform SE 7 )
OpenHab is using this formatter class and for formatting floats only a lower case f is specified.