It looks like the problem here was a branch X existed locally, and you tried to create a new branch X/Y. This won’t work, because there will be a file at .git/refs/heads/X, so git can’t also create the folder X.
However, it’s worth adding that including “origin” in your branch name points to some confusion – origin is usually the name of the remote repository. If you run git branch I expect you will see local branches with origin in the name.
The format git checkout X is shorthand for:
- look for a local branch
Xand check that out if it exists - otherwise look for a remote branch
Xand check that out locally (git checkout -b X origin/X)
To fix your current state, you can likely do this (see here):
git update-ref -d refs/heads/origin/branch