I’m having the same problem after the update to 2.2 - same solution…
+1 
For me all works fine when I removed mqtt actions (I also had to change something in mqtt.cfg to get it to connect again).
But if I install mqtt action agian, it all stops working again. Not really sure how and why, but mqtt communication works without mqtt action plugin now.
Great that there is a easy solution, but a bit unfortunate that bug builds up a fear of updating the system 
I confirm! If both are installed, binding and action, then after the update the mosquito does not work. When you delete an action, the mosquito starts to work. This happens a very long time ago.
can you try to restart the mosquito service after Openhab service is fully started and all the bindings and UI are fully loaded ?
in my case it always works after a simple restart for the service
Same issue. was starting to pull my hair out. Thanks for the solution.
This problem still exists. There is a namespace type conflict, as it is clearly referencing the action in the logs as the reason for failing.
Cannot use configuration org.openhab.mqtt for [org.openhab.io.transport..MqttService, org.osgi.service.cm.ManagedService, id=316, bundle=208/mvn:org.openhab.io/org.openhab.io.transport.mqtt/1.11.0]: No visibility to configuration bound to mvn:org.openhab.action/org.openhab.action.mqtt/1.11.0This clearly is design/implementation flaw - see https://github.com/openhab/openhab1-addons/issues/5500#issuecomment-370210029. Both o.oh.io.transport.mqtt and o.oh.action.mqtt have a ManagedService which use the same PID (i.e. unique identifier).
i just had this happen on oh 2.2.0 release. is mqtt-action needed at this stage or can it be left uninstalled?
Had the same issue with as I upgraded to 2.4.0 snapshot.
This post helped me get going again. Thanks
I had the same issue after upgrading to 2.3.0. Disabling mqtt-actions and re-enabling it solved the problem.
For anyone who is able to reproduce the action/binding conflct, try installing these 3 bundles.
This should theoretically fix the problem, as these 3 have been updated to have unique PID values.
I would test it myself, but I’ve never been able to get the problem to occur here locally.
Just updated today to 2.4 snapshot and MQTT failed.
Solved by uninstalling and re-installing MQTT action and MQTT Binding as suggested in the update to 2.2 issue. I’m running on Windows (which doesn’t have an update script) what was everyone else running?
What a crazy bug. I´ve struggeling for hours to solve the same problem. Glad to see that the solution was simple.
I let the MQTT action disabled, it isnt that important to mee. Now my lightings work again. Thanks!
Because I am suffering with having to use a legacy OH1 binding, my bindings are getting uninstalled any time OH restarts. Tonight I updated OH to SNAPSHOT 2.4.0~20181012154014-1 (Build #1389) to resolve an issue where VS Code was causing OH to restart. Of course, I had to reinstall all of my bindings (becoming a real pain!). I hadn’t noticed before tonight (probably because I wasn’t paying real close attention), but when installing the MQTT binding, I noticed that it gave me a 1.13.0 and a 2.4.0 SNAPSHOT. Of course I selected 2.4.0. TBO, I do not know if I’ve run anything other than the 1.13.0 version of the MQTT binding before today. Nevertheless, with the 2.4.0 MQTT binding, NONE of my MQTT Items functioned. I uninstalled the 2.4.0 binding and installed the 1.13.0 MQTT binding. Voila! All MQTT Items function.
I do not have the MQTT Action installed… so there is nothing to uninstall as the workaround in this post suggest. So, my question is, what might be causing this 2.4.0 MQTT binding issue? Not sure where to begin to investigate. No log messages are generated.
Any suggestions?
Thanks.
Mike
I am interested too… Do this mean that there is a 2.x mqtt binding?
And if yes where are the docs?
Is there an open issue about that?
what might be causing this 2.4.0 MQTT binding issue?
What is the issue exactly? That there is now also a 2.4 MQTT version available? Well, the reason is that there is such a binding, but it isn’t yet fully ready to be used. @David_Graeff can probably best comment on it (or rather leave him the time to finish his work on it).
re: bindings getting uninstalled…
Not that I found. I only found this December 2016 post with a workaround
Apparently the October 12 SNAPSHOT (or somewhere between Oct. 1 and this one) no longer has the MQTT 2.4.0 binding on the “ignore list” (whatever that means). With the latest SNAPSHOT, the new binding shows up in the list of bindings available for install.
Awaiting word from @David_Graeff on the state and status of the 2.4.0 MQTT binding.
When you click on the 2.4.0 MQTT binding in PaperUI, the documentation link page is not found (404) whereas the 1.13.0 binding takes you to the documentation page.
That is all as expected. As I said, the binding exists, but its documentation is not yet published to the website as it is still being finalised with https://github.com/eclipse/smarthome/pull/6339. So just keep using the 1.13.0 version and be patient.
Ooooohhh!!! Can’t wait!!