With this error message Gerrit rejects to push a commit for code review if the specified target branch does not exist.
To push a change for code review the commit has to be pushed to the
refs/for/'branch' ref (for details have a look at
If you specify a non-existing branch in the
the push fails with the error message 'branch … not found'.
To fix this problem verify
that the branch name in the push specification is typed correctly (case sensitive) and
that the branch really exists for this project (in the Gerrit Web UI go to 'Projects' > 'List' and browse your project, then click on 'Branches' to see all existing branches).
If it was your intention to create a new branch you can either
bypass code review on push as explained here or
create the new branch in the Gerrit Web UI before pushing (go to 'Projects' > 'List' and browse your project, in the 'Branches' tab you can then create a new branch).
Please note that you need to be granted the 'Create reference' access to create new branches.
Part of Gerrit Error Messages