MQTT Inbound Binding Error messages in log

Hi there,

I’ve created a simple Contact item which listens on mqtt inbound messages. The switch works fine/as expected however I keep getting (every x seconds) an error message in my logs saying the following.

2018-02-22 00:14:38.025 [WARN ] [] - given new state is NULL, couldn't post update for 'foobar'

My Item File

Contact  foobar  "Foobar"  (grp_test)  {autoupdate="false",mqtt="<[broker:mytesttopic:state:MAP(]"}

My map file


Thanks for any hints on how I could get rid of this error message.

Contact items take OPEN and CLOSED as states. ON and OFF are for Switches.

1 Like

Thanks for that hint! I’ve adapted my transform map to


Additionally I removed a periodically ping message I’ve sent from my sensor (the application that sends the messages to the mqtt broker). What I have done now is having the sensor send only openened and closed to one topic and the ping messages to another seperate topic which is not monitored by openhab.