Jenkins + Gerrit Trigger Not Automatically Building
I was just having the same problem, and it had to do with the default Gerritt setting in my job for matching branches.In your job, under Gerritt Trigger, if your Branches Pattern says "**", make sure the Type is set to Path, or else it won't match any branches.
I've actually stumbled over the same problem and it took me a while to figure out the UI, since I thought the branch and project configuration belongs to Dynamic Trigger Configuration. The configuration will basically need to look like this: 
Note: my configuration uses the Silent Mode, since I don't want the plug-in to communicate back to gerrit.