OMG, this post just saved me!
I have just upgraded from an unstable ver 2.1 something from Feb to the latest stable 2.1.0-1 and all my mqtt devices couldn’t communicate with OH2. I rely heavily on mqtt for all my house device traffic and when I couldn’t figure it out for several hours, I was about to pull out my hair.
I reinstalled MQTT Action and all is well again.
Thanks!
