I have the same problem (still not fixed), and I do not have enough reputation to comment on your post. There is a closed question here with the same question about us.
We probably had an authentication problem with Git LFS. I would recommend running git lfs env and possibly git config -l to see your current environment.
EDIT
HTTPS doesn't seem to work with Git LFS. Using SSH solved my problem.
HTTP: https: // {user} @ bitbucket.org / {repo} .git
SSH: git @ bitbucket.org: {repo} .git
EDIT 2
I used Git LFS Version 2.0.1 and decided to upgrade to version 1.5.2 to copy SourceTree congif (because cloning and clicking worked with SourceTree). And now everything works with HTTPS (I think they broke something with the new version)!

source share