Git LFS fetch stuck on 0B

When you’re running git lfs fetch --all you may be greeted with the following output:

Fetching target
Git LFS: (0 of 256 files) 0 B / 512.00 MB    

Naively you get a coffee and wait for it to finish, only to soon realize it’s just stuck.
Debug flags to the rescue:

export GIT_TRACE=1

Enabling git trace will allow you to see verbose debugging information which should soon reveal the issue.
In my case the LFS wrapper wasn’t propmting for authentication correctly and was just stuck waiting for input.
Running a regular fetch first and logging in resolved the issue:

git fetch
# Log in, and then
git lfs fetch --all