Why is it not a commit and a branch cannot be created from it?

I need to work with an intricate configuration of repositories. I have 5 of them:

1. A remote central repository on machine 1.
2. My local repository on my notebook (machine 2).
3. A bare repository on machine 3.
4. A repository on machine 3.
5. A repository on machine 4 where we do code review.

So, my understanding that it works this way:

1. On my laptop (machine 2) I clone / pull from the central repository located on machine 1.
2. I push the local repo to the machine 3 (using the bare repository as a "intermediate").

Now I did some changes on the machine 3 and I want to push these changes to machine 4. Here are the instructions that I need to follow:

1. On machine 3 do all work in your test-branch, commit.
2. Push to your bare repo on machine 3: git push origin test-branch
3. On your laptop: fetch new commits from the machine-3 repo: git fetch machine3
4. Check out your branch from machine 3: git checkout -b test-branch machine-3/test-branch
5. Fetch commits from machine-4: git fetch origin
6. git rebase origin/master
7. git push origin HEAD:refs/for/master

I have problems with step 4. I get the following error:

fatal: 'machine3/test-branch' is not a commit and a branch 'test-branch' cannot be created from it

ADDED

When I execute

git rev-parse machine3/test-branch

On my laptop (machine 2) I get:

machine3/test-branch

fatal: ambiguous argument 'machine3/test-branch': unknown revision or path not in the working tree.

Use '--' to separate paths from revisions, like this:
'git <command> [<revision>...] -- [<file>...]'

The question is complex / convolute, the answer is simple. There was a mismatch between the alias and machine3. The alias for the remote that has been used, was not for machine3. The machine3 had another alias.