Did not schedule build for branch
A suggestion found in some old IRC logs is that the "Automatic branch project triggering" option has been set to something that doesn't match the branch you want built. Set that option appropriately so that your desired branch or branches will build automatically.
As oueftete's answer suggests, make sure the "Automatic branch project triggering" regex matches your branch.
What I didn't realize (after coming back to this page and rereading that answer multiple times over the last year and a half) is that, unlike in python, a blank regex does NOT match everything. If you want to build every branch, you have to put .* in that field.