nbdiff-web <file-path> inside a git repo shows the spinner

[pinchedsquare]

Installed pip package is:

Name: nbdime
Version: 4.0.2

I have also ran:
nbdime config-git --enable for my repo.

when I run nbdiff-web <file-path> browser open correctly but there is a spinner and it shows no diff.

I have tried many combos, it looks like the only way I can get nbdiff-web to show diff is if I save the different revision of the files using git show in temporary files and then run `nbdiff-web <old_tmp_file> <new_tmp_file>

I am not sure why diffing with my remote repo doesn't work.

screenshot of nbdime show <file-path> working fine.

Screenshot of the issue:

Any help is greatly appreciated.